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Go Back   Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum > 2002 - 2009 TrailBlazer/Envoy Tech > 02-09 Vortec 4.2L I-6 Engine and Drivetrain > OEM Issues

OEM Issues Original Equipment Repairs and/or Problems

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  #1  
Old 12-01-2011, 10:26 PM
jamesm2005 jamesm2005 is offline
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2006 Chevy TrailBlazer LS
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Help with Blinking Check Engine Light

Lately I have been having some weird issues with my TB.

I have a code reader on the way, but in the meantime I was wondering if anyone else has had this issue.

At idle or sitting at a stoplight I my check engine light (CEL) will just start blinking. Once I rev the engine, or start driving again, it goes off.

I dont get a solid check engine light at all before or after this event.

When it first started, I did get a solid check engine light but after a couple starts of the truck it would go away.

I have onstar so I talked to the "techs" who have told me the code states random cylinder misfire. But not giving what cylinder.

The advice was obviously to go straight to the dealer and hand them your wallet, but then after telling the guy I dont have $$$$ to spend, he said try new plugs and fuel injector cleaning.

Got new plugs, sorry, not the ac delco brand, and did a couple treatments of OTC fuel injector cleaner.

No change. So I am wondering, what your thoughts are.
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  #2  
Old 12-01-2011, 10:31 PM
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the roadie the roadie is offline
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Wish you had shared the mileage. It's highly relevant.

Anyway, use only Delco 41-103 plugs. Change the ones you have in there now. See if you can get it to throw a code that includes WHICH cylinder is misfiring. Then suspect the coil on that cylinder. Next check compression.
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  #3  
Old 12-02-2011, 01:41 PM
jamesm2005 jamesm2005 is offline
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Yes, that probably would help. Sorry. My truck has 135k on it right now.

I had put AC Delcos in just last summer, but after talking to a mechanic buddy, he suggested that I go buy some better ones. I know TBs are sensitive to others so I will go grab some AC Delcos and switch back.

Coils I think is the problem. I do remember noticing oil residue on some of the plugs on the outside end.

Any recommendations on cleaning the coils? Can I shoot some eletrical contact cleaner up in them or is that a no no?
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  #4  
Old 12-02-2011, 03:26 PM
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I had a coil fail, luckily it's an easy fix but expensive. Here's a video from another member here to assist. http://www.youtube.com/watch?v=DjL_Wefla0s
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  #5  
Old 12-06-2011, 01:16 AM
blown4pt3 blown4pt3 is offline
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Quote:
Originally Posted by jamesm2005 View Post
Yes, that probably would help. Sorry. My truck has 135k on it right now.

I had put AC Delcos in just last summer, but after talking to a mechanic buddy, he suggested that I go buy some better ones. I know TBs are sensitive to others so I will go grab some AC Delcos and switch back.
Listen to Roadie, many others including myself only swear by the AC Delco 1=103s. I tried a few different types... and Bosch +4 platnums or whatever they are called were worst. It would bog on the 1-2 shift a bit, requiring more foot to keep it accelerating. That immediated disappeared when switching to the 41-103. Rock Auto has them right now for 5.61 each. Do that before messing with the coils. As a side note, make sure you install on a cold engine and torque to 156 INCH-pounds IIRC. If I am wrong on the torque, I know I'll get called out on it and that's ok.

The last time I changed mine, I very, very carefully added some anti-seize to the threads on the new plugs. I then took an old plug, applied a little dielectric grease to the inside of the boot and old plug, then carefully used the old plug to coat the inside of the boot by rotating the plug while seating it into the boot. Then the boot was slipped over the new plug and coil tightened down.
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  #6  
Old 12-06-2011, 03:15 PM
jamesm2005 jamesm2005 is offline
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Thanks for all the input everyone. I have more info now that I have the code reader.

I am getting a Cylinder 1 miss fire and also a code for my fuel supply running lean. (Cant remember the exact codes right now).

I picked up the AC Delco's and will install them.

Hopefully it will solve my issue. I may even switch coils to see if I can get it to happen on a different cylinder before I change plugs.

Either way though, i will change the plugs.
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  #7  
Old 12-10-2011, 03:44 PM
jamesm2005 jamesm2005 is offline
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So today I exchanged the spark plugs, cleaned the coils and I am still getting p0301 cylinder 1 missfire. I even swapped coils to see if it was the coil but it is not.

When putting the AC Delco plugs in, I also used dielectric grease.

Anyone have any ideas on what i should try next?
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  #8  
Old 12-10-2011, 06:50 PM
jamesm2005 jamesm2005 is offline
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Also, when looking at live data, I have this fault:

fuel sys 1 ol-fault

Do I need to dump this truck in the frozen river or is it fixable? LOL.
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  #9  
Old 12-11-2011, 09:28 AM
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Bad fuel injector since it is only on 1 cylinder.
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  #10  
Old 12-13-2011, 09:36 PM
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KHill KHill is offline
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A bad coil is easy enough to diagnose, just swap it with another cylinder and see if the code follows the coil. I know the frustration in trying to fix a misfire, I'm dealing with one now on the second cylinder...

A little background on mine: The misfire is intermittent and can happen every day of the week or never in a month, for about the past 6 months. I took it to the dealer and they said it was a timing problem in the engine and wanted 2000-ish to fix it. It didn't happen for a while after disconnecting the battery for 30 minutes.

My tb has 135k miles, fyi.
As a reference, my attempts have included the following:

-Replace spark plugs (no effect but needed it anyways)
-Move coil pack (resulted in P0300)
-Replace coil pack (moving resulted in a P0300 so I thought I'd just replace it instead of waiting for comfirmation, still didn't fix it after all)
-Replace o2 sensor (worked for a while, then gave P0171 with high idle for some reason, cleared and didn't return, didn't fix it)
-Cleaned connector on camshaft actuator solenoid (there was actually oil in the connector, so maybe this helped? dunno)

The result now is I can't make it misfire but it is almost dying on idle. Haven't gotten a new code as of today but it still isn't at 100%...

Next steps will be:
-Replace Camshaft Actuator Solenoid (the dealer would have done this and it's fairly cheap, also is a possibility of failure)
-Compression Test - cylinder 2

That's all I have for now. Your issue sounds a little more serious, however, seeing as the light is blinking, mine never does that. My next steps for you would be to diagnose the coil by swapping it with another, see if the problem follows the coil, and get a compression test done. Also, running some injector cleaner like techron or seafoam never hurts either and can fix a clogged injector. If the injector is beyond helping, that's a matter I cant assist in...

Good luck!
KHill
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