I have a 2006 H3 with just under 75k miles. I have had an issue with the check engine light coming on and off for about 2 years, but it never ran bad and the light would always go off, I chalked it up to the gas cap.

I recently had to replace the water pump, and since then check engine light has been on pretty much on a regular basis. At first I thought it might have had something to do with that work, I took it back and was told that replacing the H2O pump would not have caused the light to come on. When he read the codes the mechanic dismissed the random misfire result since the car wasn't running bad (and he had just worked on it) saying that the computers are too sensitive and it would turn the light on for a bad start or something of no real significance.

After the constant light I decided I had to do something. I was told the 1st thing I should do with the random misfire reading was get a tune-up. I got a tune-up and 20 minutes after I left the check engine light came back on and it started idling extremely roughly and seems like it is losing power when I first accelerate. I took it back in today and they replaced the coil on cylinder 2, as that was the code that came up. I hoped that everything would be good after that, but not even 10 minutes after I drove out of the shop the light came back on...it continues to idle extremely rough and at times feels like it might even stall out.

Any ideas? I am going back to the shop tomorrow so they can read the code and address the issue...but I feel like they are on a wild goose chase.

Sorry for the long post...and thanks in advance for any help!

 

My check engine light just came on when it hit 95,000 miles and when it did I called onstar and had them do a diagnostic report on it and the only thing they could detect was my check engine light is on and didn't detect anything from my engine,emission,or drivetrain. So I asked a friend of mine that works for a GM dealer and he said it's common for Hummer or anything GM for the check engine light come on. He told me that it's probably the o2 sensor and not to worry because GM is known for this and he said that as long as the engine is not knocking or using oil or the drivetrain is not messing up not to worry because he said I can go in there and make the engine light go back off but he said most likely it will come back on and also told me if it's bugging you that bad just take the bulb out or put a piece of black tape on it. I know every GM vehicle i've owned the check engine light usually comes on when you hit 80,000 miles and stays on. Hope this helps you out!

 

sns: I would suspect because of the rough idle, and it may even have something to do with the waterpump, that your head is going bad... I know the speculation was that on the 06ers that it would happen before 30k but there has been more and more accounts of them going bad around your mileage mark...

I would brave the storm, suck in your gut and tighten your belt, go to the dealership and see what they say... If you let in go you could do more damage to the entire block rather than just the head...

Razorback: His rough idle, to the point of stalling out, would not be in sync with a bad 02 sensor, I think that would be the opposite, he'd be running really rich, or the PCM would give him a high idle for awhile.

 

Thanks guys for your replies and thoughts. Unfortunately, it was a bad head, after some research I found that my VIN was in the sku of VINs that were effected....but I got extremely lucky and Hummer fixed it for me at no charge even though I was out of my warranty. I did find it interesting that while mine was getting repaired last week they told me that they had 3 others in there at the time, and all 4 of us were having the exact same problem fixed. I am assuming that is why they were willing to fix it under the warranty, since in reality GM really should have issued an official recall instead of just the bulletin. When I picked it up they did say I needed a new battery, which I guess is relatively realistic at 75k miles...any recommendations?

 

I've got an Optima battery on all of my vehicles and I haven't had one problem with them.

 

How about this?

 

haha, Nice!! Your alternator must hate you! :P

 

yup for the time being... until I upgrade to the 200amp

 

TTT

Can someone expound on the series of vin's more likely to have problems with the bad head ? My truck is an August 05 build, with the last numbers of the vin, 8137116.

It was not delivered until early December of 05 so my warranty just ran out...

Thanks,
Mark

 

Mark Im sure someone will chime in... however as more and more time progresses it seems that even the vins out of the range have had heads starting to fail... Im at the point where I fully expect mine to go at somepoint or another... Im wondering if my dealer would be interested in just giving me the $$$ it would cost them to fix it and I can put it towards a diesel conversion