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Trailblazer stalls at idle when defrost or A/C turns on

134K views 34 replies 30 participants last post by  chem_man 
#1 · (Edited by Moderator)
Hi, everyone, this is my first time posting on here! Ok I just got an 04 TB with 72,000 miles on it. When we first got it, the thermostat went out within a week but it was replaced and it's good now!

Now when I turn my car on and let it sit its just fine, but when I turn the defrost or A/C or just heat on at idle my car dies. The RPMs just drop out. So I took it back to the dealership and their mechanic said he cleaned some hose and recalibrated some blades. When I got back in my TB and started it up and turned on the defrost again it still dropped down into the 500's but kicked back up, but it is still dropping into the 500's a lot. I called a real chevy dealership and they told me that whatever this "mechanic" did sound like BS!

I'm thinking it's my fan clutch because my husband has an 05 TB with 73000 miles on it and it was doing the same thing and this chevy dealership replaced the fan clutch and now it has no problems what so ever. Both of our TB's started doing the same thing around the 72000 mile marker. Is this typical? What do you guys think??? What do you think the "mechanic" really did???? Any help would be greatly appreciated. :thx
 
#4 ·
The throttle body cleaning should be at the top of your list of things todo..... I changed my battery, then it idled fine but when I turned on the AC, RPM would drop to 200 compressor shut off. it would cycle rapidly 2 seconds max. RPM 600--200--600. sometimes would stall. I cleaned the throttle body and it completely fixed it all. I was totally amazed. The best $3.00 I ever spent.
Long story short, DO IT...
Steve

PS, welcome!!
 
#6 ·
stall when a/c clutch engages

Hi all, just read this older post trying to troubleshoot my problem and something grabbed my attention. I just replaced the thermostat a couple of days ago so I had the battery disconnected for several hours. Seems like this post is refering to a stalling problem after a thermostat replacement as well. Just a coincidence??? My car ran flawlessly until removing power to do a thermostat job. Could something be glitched in the tuning from a computor reset or something?? My symptoms are the exact same stalling as explained here. Just a thought, any input would be greatly appreciated. (I'm going to clean the TB of course, its due anyway)
Thanks, Jesse
 
#7 · (Edited)
Dozens and dozens of threads on stalling problems caused by the dirty throttle body.

Your problem falls under this heading as well......................yes it does.

As the tb gets dirty, the PCM adjusts the fuel mixture to allow the engine to idle smoothly (based upon info provided by the O2 and other sensors).

When you disconnect the battery..... for any reason..... the "adjustments" (discussed above) are erased from the PCM memory; and when the truck is started, the factory tune is in the memory.

The engine now has a dirty tb and a tune for a clean tb, the result is an engine that idles rough and stalls under load.

Give it some time, and it will re-adjust it'self, but the best fix is to clean the tb.
 
#11 ·
stalls when defrost or A/C turns on

I read many threads related to the stalling and mostly all replies focused on a dirty throttle body. My 04 Envoy started stalling when defrost was turned on a week ago. Pretty dangerous condition when stopped at a light.

Given the how to instructions on this site, it seemed like a job I could handle myself. Figuiring that I have to take most of the breathers and other apparatus off already to get to the throttle body, I thought it was time to do the plugs also.

OK, after 100K miles, and never had the throttle body cleaned with original plugs I found perfectly laid out instructions on this site. Easy to read, great pictures, and good examples of the typical issues that you need to be aware of when taking the apparatus off.

The throttle body was like it had baked on carbon. It was a shocker. Plugs still had the tips. Everything I read on Trailvoy talked about AC/Delco Iridiums, as the other plug manufacturers seemed to have problems a few thousand miles later.

Yep, back plug was a b*tch to get out, and I placed a 1/4" hose to get the plug out after loosing it up first with the wratchet. Same hose used to install the plug without damaging the threads too. Anti-seeze was used as instucted.

The Envoy darn near purs like new and no cut out when defroster is turned on.

I am one happy camper and glad to have found this site. Saved me a bundle also by doing the job myself.
 
#15 ·
Engine stalls when defrost is on

I just wanted to thank this website and the responses that everyone writes. I have trying to figure out why my 2004 GMC Envoy was bogging down and stalling. A mechanic at Meinike said it may be the throttle body and stated that it would 300.00 to replace it. Another mechanic said it was the ac compressor that was bad and that I needed a new one at the cost of 500 to 600 dollars to replace with a new one. Another mechanic had no idea what was going on. After reading these threads, I took it upon myself to get a can of throttle body cleaner on my way to my family reunion and see if I could clean it out. I had the TB taken out, cleaned, and put back in within an hour. Completely fixed the problem! Thanks a million (or at least 300). I will definitely check this site out before taking it to a mechanic.
 
#16 ·
faulty exhaust cam shaft solenoid

I have a 2002 TB LTZ in which for the past six months was dropping RPM and stalling once a day-- from a cold start. After a quick search on the Internet I did the followings:
1- Cleaned the Throttle
2- Had the throttle body under vacuum test over night
3- Changed the gas filter
4- Changed the air intake sensor

Guess what , I did all of the above to no avail.
For the past two weeks, the RPM drops and stalls were occurring every five minutes at all times. I was freaking out and fuming. After taking it to a garage the guy visually found the culprit. It was the exhaust cam shaft solenoid, which was leaking oil. I hope you learn from my experience.
 
#21 ·
Another happy camper here! I charged my AC and nearly had a coronary when my just purchased (1 week ago) 2004 Chevy TB started dying and couldn't idle. I cleaned the throttle body as instructed and was absolutely elated to have it purring like a kitten again. Thank you all so much for saving me a trip to the ER.
 
#25 ·
i bought a 2002 chevy trailblazer about 4 weeks ago, the car worked fine for 2 days before it started idling low and just cutting off at redlights, the check engine light came on and i had it read code came up as p1441 , it has now been in the shop 3 different times for a total of 12 days. the dealer insists on sending to his mechanic as hes paying for it, however the first time they replace the throttle body, canister and filler tubes. i got the car back after 3 days and it was still idling low shutting off at redlights and check engine light came back on after 2 days same code. took the car back and they insisted it was the throttle body replaced it again. this week was the 3rd time replcaing the throttle body. im not a mechanic but at this point im sure im being screwed. can anyone tell me what is causing this code and my car to idle low and shut off? the throttle body has now been replaced 3x, the canister once, the filler tubes an gas cap. and this is still happening to me.(may add the car now not only shuts off n idles drop at redlights but also in reverse just not while the car is in park):confused:
 
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