H3 Idling Rough - Head Problems?

My H3 with about 17,000 miles started to idle rough a while back. Otherwise it seems to run good. No real loss in power. I'm wondering if this means I have head/cylinder problems? It seems to get worse if I use certain electrical items when idling, like power windows or step on the brake etc.. Just wondering if anyone has any insight on this. Mine was one of the earlier 2006's built.

I think everyone that has had teh head/valve issue also had a check engine light for a misfire. The rough idle condition you are having will get worse when elctrical items are used just cause taking more juice will lower the rpms slightly and cause more rough idle. I would check the obvious first, air filter, type of fuel, normal stuff like that.

Replace the MAF and see if that fixes it..

the MAF should send a code as well I think Dennis? also it's kinda expensive to replace one to to see if it fixes it. I would definately bring it to the dealer for that.

As previously stated in several posts, my "check engine light"  did NOT ever come on (thru a week of driving it after it began to idle ROUGHLY)....I only knew it was an engine misfire code thru OnStar's informing me.

thats strange because the only way onstar would know of a misfire is if the engine sent a code, which also should have tripped the light at the same time.  thats very strange...not saying your a lier...just saying thats odd that the light didn't go off.

Honest engine ( being PC LOL) hun,  the light never came on.  In fact it happened 3/4 of the way to the mountains immediately after we had just done a refuel, so we thought "OK, maybe we got bad gas."  The rough idling continued thru another couple tanks and us thinking maybe we should put some additive in it????  Coincidentally when we made our destination, it happened to also be on the same date my monthly OnStar email report comes...it contained an "emissions problem" message and to call Onstar for which I did.  They then ran a diagnostic test and said all they could tell me is the diagnostic "showed an engine misfire at some point and to proceed to my nearest dealer." Of course no dealer to proceed to in the mountains, so we chanced it until we got home and I took it into the dealer the next day...got the dreaded head news. OK, so does my check engine light not work properly?????

quote:

ORIGINAL: LawWyfe

 OK, so does my check engine light not work properly?????

 
try cutting some random wires under the hood, that should tell you if the light works or not.  i'd start with a plug wire, or something coming off the injection or air intake, just not the battery cable . . . .

LOL OK SB...are ya just messin with me too?  And just what do I do then after I cut these wires?? (besides tape em back together LOL)

now that i think about it, it would probably be easier to just cut the serpentine belt.  then you can take it to the dealer and have it replaced under warranty, as well as whatever else breaks once you do that.  but, you'll at least know if the check engine light works . . . .

LawWyfe
 
just unplug a sparkplug  wire and  drive it around some..this should  set the light off 

Thanks guys...I am thinkin this would be my best bet and least damaging in light of my lack of mechanical knowledge LOL...my luck I'd cut a wire that holds everything together LOL

quote:

ORIGINAL: LawWyfe

Thanks guys...I am thinkin this would be my best bet and least damaging in light of my lack of mechanical knowledge LOL...my luck I'd cut a wire that holds everything together LOL

 
Just put Diesel fuel in your gas tank.  You should find out REAL quick if your check engine light works......  

easiest way to see if your check engine light works is to not put the gas cap back on. You'll get the light for that too. I've had that happen a few times to me already.

quote:

ORIGINAL: LawWyfe

Thanks guys...I am thinkin this would be my best bet and least damaging in light of my lack of mechanical knowledge LOL...my luck I'd cut a wire that holds everything together LOL

 
WHOOOOOAAAA - i wasn't serious when i said cut wires under the hood (but the belt comment was semi-serious).  now i'm gonna lose sleep thinking that somewhere, there's a disabled hummer because of my advice . . . .

quote:

ORIGINAL: importkiller

easiest way to see if your check engine light works is to not put the gas cap back on. You'll get the light for that too. I've had that happen a few times to me already.

 
yep that will work too  and  filling up w/ gas w/ the motor running will do it to

don't think filling up with the motor running will trip the light if the cap is put back on tight. I have never shut the motor off while getting gas and as long as the cap is put back on tight the light never comes on. Theres a vacumn sensor or something in the system for the cap.

The system only checks this gasoline vapor emission system after you have driven 20 minutes or longer and then only after you turn the key off and stays off for 10 minutes or more..Only then will it store a code and indicate on the next start up (SES) and will correct itself if the cap is placed on properly during or before the next full cycle as stated

I duuno, maybe like the TPS system mine is messed up. All I know is that if I get gas and don't put the cap on tight my light will turn on in less than 2 miles....every damn time. It's like clockwork.

Hmmm..Interesting..yours does have some out of the ordinary chit going on..for example the terrible gas mileage, but runs faster than any other stock H3 on the road...That one really blows my mechanical mind.

don't know about any other stock h3 on the road, but I know I was faster than the one I ran against.
 
I love the h3 as a truck...I just hate mine. Which Is why I said for my one year anniversary that I was going to drive it off a bridge
 
 

I am having the same problem. I have a 2007 H3 with a little over 2,000 miles and it just started a few hundred miles ago. (Rough idle) When I took it back to the dealer they told me that it was normal that it is a unbalanced engine and that is a draw back to the V5. That is wierd to me because it didn't do it when I brought it. This just started shortly after putting in a new radio then traction control button stopped working as well around the same time?  Why is the MAF??

quote:

ORIGINAL: PhxRealtor

My H3 with about 17,000 miles started to idle rough a while back. Otherwise it seems to run good. No real loss in power. I'm wondering if this means I have head/cylinder problems? It seems to get worse if I use certain electrical items when idling, like power windows or step on the brake etc.. Just wondering if anyone has any insight on this. Mine was one of the earlier 2006's built.

My H3 was built in March 2006 and has had this problem, plus many more.

The rough idle started at about 20,000 on mine. Over the course of a month it transformed from minor shaking in idle and steering wheel vibrations, to dropping rpms in 1st gear while driving and at idle. Eventually the engine light came on flashing (along with shaking like I was driving over rocks) and OnStar ran a diagnostic. Misfire signals, said it should not be operated to prevent serious, permanent damage and it had to be towed in.

It is definitely worse when you brake, use A/C, other electrical. After the repair, my battery started going dead frequently and they just replaced it. Only at 24,500 miles.

I was told that the car had been running on 4 cylinders, likely since mile one because of bad valve casting- replaced the head. They said they repaired it, but it is still idling rough, worse in reverse, and the Dealer said they do not see anything wrong.

I also had the heater core fail at 9,000 miles when it was 38 degrees outside. Windows began fogging followed by anti freeze spewing through air vents while I was driving. Ever since the repair, the passenger side has a rattle- which dealer has said they repaired, but still makes noise.

Am on 4th chrome grill because of #1's chrome flaking off, the repair people ruining #2 when working on the head/valve problem, and the 3rd one developing orange oxidation spots all over.

I wanted to love this vehicle, but I am sadly dissapointed.

Hey Brad, missed your earlier newbie email. Welcome - we live in the same zip code! See you around (or at least after we see a pic )