Unstable idle or hesitation on takeoff? Clean the throttle body! [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum

: Unstable idle or hesitation on takeoff? Clean the throttle body!


pervisanathema
06-03-2006, 11:28 AM
My truck was suffering from an unstable idle (would drop by several hundred rpms then rebound) and slight hesitation on takeoff. Yesterday I thoroughly cleaned the throttle body. The problem was completely eliminated. BTW, I have ~54k miles.

Envoy Fan
06-03-2006, 11:45 AM
Got any pics?

pervisanathema
06-03-2006, 04:46 PM
Got any pics?

No, I used the pics in the Hayne's manual to guide me so I didn't take any of my own.

ehall0527
06-03-2006, 04:53 PM
I just clean my throttle body yesterday as well...it made a huge difference. I had disconnected the battery the day before to install a DRL-Killer and the car "forgot" how to run with that dirty throttle body and began stalling with the A/C on. A little throttle body cleaner from Autozone and about an hour of sweat and stretching across the engine took care of the problem.

(Sorry I didnt take pictures either, kinda hard with greasy hands, I thought about it though)

blktbon20s
06-03-2006, 07:05 PM
did u guys take the whole T/B out? or did u just spray somecleaner while still bolted on?
I just put in a TBS and cleaned it but i don't think i cleaned it enough, and i don't want to disassemble everything again.

aa_had
06-03-2006, 11:27 PM
My Envoy is doing the same I was wondering what the problem was. I will try that tomorrow. I am curious also do I need to take everything apart?

ehall0527
06-04-2006, 12:20 AM
did u guys take the whole T/B out? or did u just spray somecleaner while still bolted on?
I just put in a TBS and cleaned it but i don't think i cleaned it enough, and i don't want to disassemble everything again.
I just left the throttle body assembly on the engine, but I know a few here have taken it off here before. I really wasnt comfortable taking the whole assembly off, but it really doesnt look too difficult. I just spent a long time cleaning it. I dont think I could have gotten it too much cleaner even with taking it off. It's just hard cleaning behind the "throttle flap" (I have no idea what the real name is), but I managed.

majorpain
06-04-2006, 01:44 AM
I was wondering what product is best used for cleaning your throttle body??
I think of safe then successful.
I know there is a lot of products out there that can do more harm than good, so a good product will also extend the life of the engine.

I have the same problem with my TB and have been putting it off.

J.C

pervisanathema
06-04-2006, 08:43 AM
I was wondering what product is best used for cleaning your throttle body??
I used Valvoline throttle body cleaner which I purchased from Advanced Auto for ~$4. It stated on the label that is was safe for O2 sensors.

My Envoy is doing the same I was wondering what the problem was. I will try that tomorrow. I am curious also do I need to take everything apart?
I left the throttle body on the vehicle. I *gently* opened the butterfly valve with my fingers to clean behind its edges and the area behind it. You do not want to bend or warp this piece.

Also, just as a general FYI, the truck ran like crap when I first started it up after cleaning. It was just burning off the can of cleaner that I sprayed down the throttle body. Exhaust was white and smelled like the cleaner.

Menthol
06-04-2006, 09:26 AM
Take it out if you're comfortable doing it. In depth discussion here

http://forums.trailvoy.com/showthread.php?t=5814&highlight=Throttle+Body





My Envoy is doing the same I was wondering what the problem was. I will try that tomorrow. I am curious also do I need to take everything apart?

Shamrok
06-05-2006, 10:30 AM
It's much easier to clean if you take out the whole TB. That way you can clean the inner side of the butterfly with ease. If you're going to take the time to clean it then you might as well clean it good. I have a K&N CAI so it made it much easier to remove than having all the stock plastics on.

ehall0527
06-05-2006, 10:36 AM
Can anyone make a good recommendation on how often the throttle body should be cleaned?? I should be good for a while since I just cleaned it, but I wanted to know about how often it should need a cleaning.

rbarrios
06-05-2006, 12:43 PM
ehall..... your problem was just like mine... when I put in a new battery.... I left it all disconnected while I cleaned the battery tray.
Upon the 1st use of the AC... it ran like crap and the rpms dropped in cylcles and the compressor came on and off every 8 seconds or so... and it ran like crap with AC on only.
with the TB cleaning, it works great (als disconnected battery for about 30 min) so that it would forget the faulty settings....
I used the red can ot TB cleaner. $2.50 or so.
best $2.50 spent....

big_angry
09-08-2008, 06:32 AM
Yeah, I went to autozone and the problem, according to him, was the idle control valve. Negative. The idle control valve is all one piece with the throttle body. I installed the brand new OEM GM throttle body and.....nothing. AAAAH!!!!:x:mad:

p.s. I disconnected the battery for the hour that it took to uninstall the old and install the new throttlebody. 4 bolts, and two wire harnesses. That part was fairly easy.

dretoya
11-12-2008, 02:57 PM
All of these quotes sounds like my problem to my truck..i was getting frustrated trying to figure it out..the code from auto zone read fuel too rich...that could be anything..I use Premium gas...but that did not make since to me. So now all the talk about the throttle body is what I am experiencing as far a shutting off..air condition..idle high..hesitation...i need to get started.. I do not mind getting dirty to be safe..

ss_hobby
11-16-2008, 12:41 AM
I don't get it. I can't figure this one out. I pulled the throttle body and cleaned it, replaced the gasket(good luck finding it at other than Chevy), went ahead and replaced the spark plugs with Bosch Platinum 2's. I am no longer experiencing a full stall but I do get a dip in the RPMs like its gonna stall.
It doesn't happen all the time but it happens enough, that I want to watch the RPMs to make sure I don't have to throw it into park and restart the truck in traffic. Pretty much it happens after its warmed up, the A/C is on, in gear and with my foot on the brake. I have been trying to pay attention to see when it happens. I have noticed that the brake peddle drops when it gets ready to do it. Seems like a vacuum problem to me. I am also experiencing a hesitation in acceleration from a dead stop. I mean dead stop because again I have been trying to watch this and if I let the truck roll forward before I hit the throttle it doesn't seem to happen.
I had a similar problem with my 2003 Mazda Tribute and I replaced the coils, which seemed to fix the problem.
Any suggestions and help on this one guys?
Love the truck by the way...pulls the boat like it wasn't even there.

Foosh
11-16-2008, 12:52 AM
thanks, that would actually solve a big problem of mine, during idle i'm boncing up to 400 rpms

dretoya
11-17-2008, 07:01 PM
SS Hobby..I am having the same exact problem... I have tried absolutely everything.. Maybe we can try to figure this problem out together...I am so frustrated right now.

ss_hobby
11-17-2008, 07:27 PM
LOL...I know its not funny but daaaaaamn!!!!
Lets see. Since I have replaced the sparkplugs, air filter, fuel filter, cleaned the throttle body by taking it off and replacing the gasket(ps. don't drop it), changed the tranny fluid, changed the diff fluid front and rear(thats when I found out the front driver side seal was blown) and ...soon to change the transfer fluid, the problem is getter better.
I know the diff, tranny and transfer case have nothing to do with it...I just went ahead and did the work.
I no longer am stalling out...very good thing. I went ahead and ran a full tank of 93 octane through the truck with a bottle of lucas fuel injector cleaner. I drove the truck today all over the place and only had a couple of times where the hesitation was present and not once did it try to stall out. I may be onto something here!!!!
I think I am going to my mechanic and have him hook the truck up to a fuel injector cleaner. He said he would do it for $100. He bypasses the fuel tank, filter ect and hooks directly into the line going to the injectors and cleans them out. I will keep you all posted but I think its injectors just being dirty. The throttle body was absolutely filthy by the way. I had to use my finger to wipe the crud off. Also, make sure you disconnect your battery for 30 minutes after you do something that you may think will improve your idle. The truck will learn the "clean idle" not the old "dirty idle".
I have also considered the coils and found a guy in Miami that sells a set for just over $120 including shipping.
Last thing of course but I don't think its the problem is to reflash the PCM.
Keep your fingers crossed!

Super 88
11-17-2008, 07:51 PM
I don't get it. I can't figure this one out. I pulled the throttle body and cleaned it, replaced the gasket(good luck finding it at other than Chevy), went ahead and replaced the spark plugs with Bosch Platinum 2's. I am no longer experiencing a full stall but I do get a dip in the RPMs like its gonna stall.


Many people on this forum have had trouble with Bosch plugs in these SUV's. Personally I haven't ever tried them in any vehicle so I really can't comment - just saying what others (many) have said.

petevw
11-17-2008, 07:54 PM
I have also considered the coils and found a guy in Miami that sells a set for just over $120 including shipping.

All you guys cleaning the throttle body, much better to remove it and clean the whole thing, plus you don't shoot all that cleaner down the intake. And as you said, disconnect the battery for at least 30-45 min.

BTW, if those coil packs that the guy in Florida was selling are name brand, and new, that is a great price!! Cheapest price for the OEM Delphi that I've seen is at Rockauto.com....$49.79 ea. + shipping.

Foosh
11-17-2008, 07:55 PM
i'm going home this weekend and am definately doing this, this was an extremely informative/ helpful thread!!!!

ss_hobby
11-18-2008, 08:03 AM
Yea, those coils are supposed to be new OEM. I purchased a set of coils from this guy for my Mazda Tribute and they were new OEM. It seemed to help the Tribute with a similar problem. Its just too hard to diagnose a problem like this because its intermittent. If it would cause the engine light to trigger it would make life a whole lot easier. My mechanic is telling me it sounds like an electrical/coil problem...we'll see.
I noticed something last night though. Driving slowly down my road I noticed my headlights dimmed for a sec. That would seem like an alternator problem to me and I am wondering if they are related. Again, that doesn't happen all the time just like the idle. HMMMMMMMMM
Is anyone else with the same idle problem noticing the headlight dimming?

wardak33
11-18-2008, 08:30 AM
:iagree: i had bosch platinums +2 in for about a couple thousand miles (3-5k miles). i decided to change them out about a month ago and when i looked at them, they looked like they were on for 100k miles! they looked like crap and i just couldn't rely on them. i changed them to champion double platinum, mostly because i change the plugs in both my cars at least once a year (twice a year in my galant because i'm running ngk v-power copper plugs).

wardak33
11-18-2008, 08:33 AM
Yea, those coils are supposed to be new OEM. I purchased a set of coils from this guy for my Mazda Tribute and they were new OEM. It seemed to help the Tribute with a similar problem. Its just too hard to diagnose a problem like this because its intermittent. If it would cause the engine light to trigger it would make life a whole lot easier. My mechanic is telling me it sounds like an electrical/coil problem...we'll see.
I noticed something last night though. Driving slowly down my road I noticed my headlights dimmed for a sec. That would seem like an alternator problem to me and I am wondering if they are related. Again, that doesn't happen all the time just like the idle. HMMMMMMMMM
Is anyone else with the same idle problem noticing the headlight dimming?

just because there isn't a CEL or an SES light doesn't mean there aren't any codes. Sometimes the PCM may store "pending codes," which are still there, but not trigger a light.

ss_hobby
11-18-2008, 08:51 AM
I will have him check for pending codes today and will let you all know. I don't mind replacing the plugs...it's a pretty cheap to do. The first plug and coil is the only PITA. That stupid tray holding the wires. I don't know if I am going to change the plugs out just yet. I didn't seem to get worse but it did seem to improve it slightly.

lamnator
11-19-2008, 02:08 PM
you dont want to move the throttle arm while the battery is still attached. The stepper motor will still have power to it and it can cause problems to the motor. If you want to get behind it, just undo the four 6mmx45mm screws and clean it. :)

ss_hobby
11-19-2008, 06:34 PM
Absolutely, pull the throttle body. You can't get all the dirt off without doing so. Also, you will more than likely have to hit Chevy to get the rubber gasket.
I had the mechanic hook it up. There were no pending codes. I am still experiencing occasional hesitation at initial acceleration.

ss_hobby
11-29-2008, 04:44 PM
I found this while trying to diagnose my issue. This is from the pcmforless thread.

[Quote:
Attn: 2004 Trailblazer/Envoy Potential Customers
If you have a 2004 Trailblazer/Envoy and are considering a tune from us, please read this message fully first.

We have encountered an issue with some 2004 models pertaining to a TSB that has been issued. While you may not notice a problem now, something about the tune seems to exacerbate the issue, making the truck feel like it stalls, or making it actually stall.

If you are using the core program, this will not apply to you, as we start the cores with a fresh GM calibration that will have the update. However, if you are sending your PCM in or using the loaner program, please read the following:
Quote:
If the 11th digit of the VIN is a 2 and the last 8 of the VIN is less than 52114278 or if the 11th digit of the VIN is a 6 and the last 8 of the VIN is less than 56105324, reprogram the PCM with the latest calibrations. An updated engine calibration has been released to address this issue (intermittent stall or near stall during low speed deceleration).

My vehicle is affected, what now?

There are a couple ways to deal with this. You can stop by your GM dealership and get the updated calibration before sending the PCM in or using our loaner program. Or, you can consider changing to the core program, which will start you out with a fresh calibration including the update.

So, as you have been seeing in this hijacked thread (sorry), I have been trying to isolate the problem. I ended up getting a second set of coils and I had the same problem. I found this information and my trailblazer falls in this category. I brought the trailblazer over to the dealership. Suburban Chevrolet of Stuart is full of idiots. I knew more about this truck then these guys did. I told them about my problem and all that I have done to fix it. I said to them, "I believe my vehicle falls into the category of this pcm flash/fix." I even printed out the TSB and all of this information. They said they would have to diagnose the problem before they could fix it. :duh: They refused to run the flash until they ran through and eliminated all other possibilities. I called them after the second day and asked how they were doing diagnosing my problem. They didn't find the problem and said my pcm already had the updated code. Since a pcm is like a computer and can get corrupted or missing files , I told them even though it has the updated code I wanted them to reflash. They finally agreed that this may be the only solution and re-flashed my pcm. It still seems like I have the intermittent hesitation but it hasn't stalled yet. By the way, I got into the truck and the RPM gauge was reading 5000, which was working fine before I dropped it off. I jumped out and told the service clerk. He immediately ran it over to the mechanic then was back 2 minutes later. I said "Oh that was a quick fix". Apparently not, the mechanic claims that the RPM gauge was like that when he got into the truck and the gauge cluster would have to be replaced to fix it. :mad: I argued with the idiot for awhile and finally grabbed my keys and left. So, I figured out how to fix that easily. I turned the truck on, I turned the truck off, I turned the truck on, I turned the truck off, repeat 8 more times. Tada!!! Everytime I turned the truck off I heard a pressure release sound coming from the dash/tach. Wouldn't that be wonderful if that was the problem...a vacuum leak off the tach. Does the tach even run off of vacuum? So, as we stand right now...I don't know if this is fixed or not but I will keep you updated.
I am really starting to hate this truck...
You all might find this on trailvoy.com for sale.

ss_hobby
01-01-2009, 09:07 PM
Sorry it took sooooo long to add to this.
Going out on a limb, I purchased a new upstream o2 sensor. I have spent 2 weeks off and on and a 1/4 of a bottle of pb blaster trying to get that stupid #$%@ sensor out. I finally decided to see what would happen if I disconnected the harness all together. WOW:woot:...what a difference in the way the truck runs. I now have been driving the truck for 1 week with it disconnected and the engine light on. Not once have I experienced hesitation, not once has it tried to stall out on me. I now have better acceleration and I don't get that annoying high pitched whining noise for 10 seconds at cold startup. I do have to admit though that the idle is high now...around 900-950. That does have an impact on air controlled devices(BRAKES!). The peddle is much harder and since the idle is so high it does affect stopping. Before I did this though it seem like the peddle was too soft but what do I know. I borrowed my buddies impact wrench and am going to try to get it from the wheel well with an angle attachment. It's just hard trying to convince my wife that she should help. I plan on heating the engine to running temperature and holding the socket on the sensor while she tries to drive it off with the impact gun. Last try will be with my propane torch.

ss_hobby
01-04-2009, 04:13 AM
I finally got the o2 sensor out and the new one in. I went down to my mechanic and he let me use the scan tool to reset the codes, since I have been driving without the sensor hooked up. Viola, RPMS returned to normal and so far, with the a/c on I have not experienced hesitation. The o2 sensor was completely caked in carbon buildup, alot like the backside of the throttle body. I would imagine that if I could have just cleaned the o2 sensor it would have done the same. I had the replacement already and I had messed up the o2 sensor so bad trying to get it out, that replacing it was my only option.
I will check back in a week and let you know how it's running. I will also at that point post a new thread covering this as another solution to the hesitation problem.

ss_hobby
01-10-2009, 12:56 PM
That seems to have fixed the hesitation problem. The only problem is I am throwing a code now. I am going to post this problem on a new thread. But basically I am throwing a p0172 and p0410 code. After resetting the code twice I noticed that it will not come throw it again until the next morning when the truck has been sitting. I also noticed that the RPM's stay high for the first couple of minutes of driving (900-1200) and then drop off to about 650.
As far as the hesitation its finally gone, the stalling is not an issue anymore.
Upstream O2 sensor!!!!

carlocote
04-21-2009, 12:10 PM
That seems to have fixed the hesitation problem. The only problem is I am throwing a code now. I am going to post this problem on a new thread. But basically I am throwing a p0172 and p0410 code. After resetting the code twice I noticed that it will not come throw it again until the next morning when the truck has been sitting. I also noticed that the RPM's stay high for the first couple of minutes of driving (900-1200) and then drop off to about 650.
As far as the hesitation its finally gone, the stalling is not an issue anymore.
Upstream O2 sensor!!!!

Hello

I got your problem with high RPM. Sometimes they are around 950 and stay at least for a week, suddenly they drop to 650 apparently with doing nothing

Should I check/replace my O2 sensor?

thank you for helping me

Carlos from South America....:tiphat

ss_hobby
04-21-2009, 08:10 PM
I have pretty much given up on my issues. I am still throwing a code but the truck is running fine.
I am not sure why your RPM's stay high all the time. The only reason my rpm's consistently stayed high was when I had disconnected the upstream o2 sensor all together. Try disconnnecting the lead and see if it makes a difference on your RPMS. It will throw a code. You may want to buy some electronic connector cleaner and spray out the connecter too. It was EXTREMELY difficult to get the old O2 sensor out. Either the factory cross threaded it or it just was that corroded. I ended up cutting the leads, soaking in a half can of penetrating oil and putting an impact wrench on the sensor. Even after all that I still couldn't get it to budge...I worked on it for 1 week off and on before I finally got it to move.
My other issues that I have with the truck are...RPM gauge malfunctions occasionally...and there may be a ground issue somewhere, because I get on hell of a zap when I go to close the door after I have been driving around 50% of the time.
I have never had so many problems with a vehicle before. I am very dissappointed with this truck.

Super 88
04-21-2009, 08:38 PM
It was EXTREMELY difficult to get the old O2 sensor out. Either the factory cross threaded it or it just was that corroded.
Wow, that's too bad. I had the exact opposite experience. It took me about 15 minutes start to finish when I changed mine - and probably 5 of those minutes were spent looking for my 02 socket.

ss_hobby
05-03-2009, 07:30 PM
I finally decided to tackle the issue again because the engine light was starting to burn my retinas. I pulled the A.I.R. Pump off and hooked a couple of wires to a 12v battery and to the pump. It ran but sounded terrible. I went ahead and ordered another pump and 2 days later after the install the light is off. It was running but not at full speed apparently. I am going to try and take the old pump apart and see what happened. I imagine it was corrosion from the water that was in it. I already replaced the check valve so hopefully I won't have that issue again.
This all started with hesitation and stalling issues without a check engine light on.

ray94513
10-25-2009, 01:55 PM
does any one have how-to pics to do my 5.3 ltr ?the reason i ask is that i really dont want to break anything ,from only spending 3 dollars to spending 300 dollars:confused:,(:hail: for help)

Bill Mush
11-03-2009, 04:58 PM
My Envoy was stalling anytime the heat/AC was on at stop lights. After reading the postings on Trailvoy I cleaned the throttle body (167K miles) and as advertised my truck is now running better than ever...Much smoother acceleration and more pickup. For $4.00 worth of spray cleaning solvent and less than an hour of my time it really made a big difference.

pcharm129
07-18-2011, 08:27 PM
I am having the same issue as many of u guys, with my truck stalling, vibrating hard, hesitant starts (if I floor it from a standstill it will creep and do about 10 mph by the time its a block away), and fluxuating RPM's (bet. about 700 & 1000). Chevy told me that I have a bad throttle body and wanted to charge me $580 to fix it! I have since cleaned it but I have noticed no difference. However, what I did notice is that the throttle body's butterfly does not open more than about a quarter inch max when the gas pedal is pressed to the floor. I'm sure it's supposed to open more than that, but I'm not sure of the criteria for it to do so. Does the truck have to be in gear? There is a limiter on my truck (she won't even do 100mph). Can that be preventing it from opening all the way. Or is Chevy correct and I need to replace it? I don't want to spend money replacing it and it turns out to be a tuning issue...

Snaps619
01-07-2012, 03:33 PM
Honestly, i say just take the TB off. Its really not that hard at all and it insures a good cleaning. If you take off all the intake stuff then you might as well do it in my opinion. I just did mine and it was horrible, it obviously hasnt been done. Anyways just thought id throw in my two cents. Good luck with whatever approach you decide to take!:m2::thumbsup:

thomaschevy
01-30-2012, 02:32 PM
Yea, those coils are supposed to be new OEM. I purchased a set of coils from this guy for my Mazda Tribute and they were new OEM. It seemed to help the Tribute with a similar problem. Its just too hard to diagnose a problem like this because its intermittent. If it would cause the engine light to trigger it would make life a whole lot easier. My mechanic is telling me it sounds like an electrical/coil problem...we'll see.
I noticed something last night though. Driving slowly down my road I noticed my headlights dimmed for a sec. That would seem like an alternator problem to me and I am wondering if they are related. Again, that doesn't happen all the time just like the idle. HMMMMMMMMM
Is anyone else with the same idle problem noticing the headlight dimming?

I'm having the same issue with headlights dimming, is this coil pack related? My alternator is even overcharging. But no CEL ON or DTCs in computer.:crazy:

mike86544
05-14-2012, 05:41 PM
i have cleaned the throttle body!!! do i use i whole can down the thing or what??? plus its still doing all the same issues... SOMEONE HELPPP!!!:duh::suicide::suicide:

Strom
05-14-2012, 10:17 PM
i have cleaned the throttle body!!! do i use i whole can down the thing or what??? plus its still doing all the same issues... SOMEONE HELPPP!!!:duh::suicide::suicide:


You have to remove the throttle body and disconnect battery and use cleaner that is specific for throttle bodies *walmart has it. You cannot reach the grim and varnish without removing it. And battery must be disconnected for at least 20 minutes, takes a little longer than that to clean it properly. There are several write ups on that. Also several threads on use of seafoam. Just search for those topics and many informative threads will show for each topic. Have to follow them though and not take short cuts.

Snaps619
05-15-2012, 07:54 AM
What Strom said :thumbsup:

mike86544
05-15-2012, 03:56 PM
ive done all of that still having the issue.. i left the battery disconnected for at least an hour while i cleaned it. ive foamed it once but still nothing.

Snaps619
05-15-2012, 08:39 PM
And you actually went in with a rag and wiped it clean? If you cleaned the hell out of it and it didnt work, then you may have some other issue. Normally it hesitates when the heat or ac is on. That shoulda fixed it. Try a forum more detailed on that, im not sure what else it could be...:undecided

big_angry
05-15-2012, 11:32 PM
I replaced the o2 sensor on my 05 envoy. Problem solved.