I have just had some bad news today, I took my 06 H3 in because the check engine light would come on for a few days then go off then come back on for a couple of more days. Made an appointment at my local Hummer dealer and they said oh yes we put it on the computer and we fixed the "sensor". I did not even get half way home and the engine light came on again, I turned around and took it straight back and said It was back on, he goes yes we know what it is we will have to order a NEW Cylinder Head. WHY could he not be upfront and honest in the beginning which scares me more than anything. He told me it is on order and should take awhile to get. I have bought this vehicle NEW in 05 and had no prior problems with it. It has 40,000 miles on it and has been a great car. NOW I am worried I will be stuck with something that is going to turn out to be a major pain. To me this is very serious stuff. I don't trust replacing the head will not mean that this original issue will just compound into other issues. I am seriously thinking of dumping the hummer once it has been repaired. Since reading the forums I am finding out this is more common than not. I wish GM would step up to the plate and let us unsuspecting H3 owners know about these widespread issues so we can get them repaired sooner instead of later.Should I be as upset as I am feeling????

 

The problem GM has is with the intake valve seating properly,if it leaks you get a misfire at idle only.If you get a miss at other throttle positions than idle,then you don't have a cyl.head issue,but possibly injector or coil on plug shorting out,I've found alot of #2 cyl.coils corroded due to water leaking in through the hood plate directly above cyl.2.The head issue has a cutoff point.the last 6#'s of the V.I.N.287591,if anyone has a V.I.N. lower than the cutoff then you may have the issue.any number above the cutoff already has the hardened seats.It's also more noticable in colder climates,and usually only in the winter months.hope this helps! WK

 

https://www.hummerforums.com/forumid_224/tt.htm

 

Hi, I recently had engine light on n off reading misfire 2, what does this mean? How much does this cost to fix? Worried a girl with no idea about this? Live in TC, CA any idea where I can get checked to b sure?

 

how many miles on her have you tried to replace plugs

 

I have 62,500 miles, haven't done anything to it yet? Don't trust just any place so not sure where to go?