Skipping Hummer h2

[Yetti]

well I have to assume a lot here. first off is the engine making any odd noises when the skip/miss happens? if it just dies in corners and then re starts then I would be looking at a short of some kind. H2 are famous for having bad ignition switchs. like if it does it on right turns and not lefts the weight of your key ring could be causing it.

as for no engine codes I would look at fuel pump drop out or ignition. the best way to check your coils and plugs is to squirt water on them with a two liter pop bottle with a hole in the lid. water down each one while its running to see if it misses when wet. if you can pin point it you can probablly fix it easy.

[cathyiam]

Hey. Thanks for the advice. We have noticed over the past 2 days that if it starts doing it-it does it like I said mosly of the morning,but it starts when we hit 55 mph-it will do it constantly if you stay @ 55, but when you go over 55 it stops. the rpms jump the whole time it is doing it. We will check the key ring,but it doesn't die all together-it just skips like it's running out of fuel. It has been doing it for at least 5 months and has not got worse. We have had it to the Chevy place because the nearest hummer place is over 100 miles away- they changed the rear diff fluid and the fuel filter,but did not know what else to do. I will try wetting the coils and spark plugs. Another mechanic told us to crank it @ night and see if a spark jumped off the coil, but no luck.

[La.Swamp Lobster]

Sounds like one of the knock sensors is bad...had to have mine replaced last week...was running rough as a leaf licker on a republicans hairy butt...and had very little power. The H2 has 2 of them, and they are located under the intake..but this should show a code when tested...but then again it could also be a cad. converter that is clogged up!

[PaHumBug]

Mine did this the other day for the first time. Hasn't done it since. I got the feeling it was the tranny trying to shift in and out of OD. I gave it gas to make it down shift and it quit. Hasn't done it since. If yours is doing it at 55mph, maybe thats the same thing. My check engine light came on, but went back off the next time I started it. Since then the check engine light has come on every once in a while, but turns off soon after. Does the light need to be lit in order to get a code?

[PaHumBug]

Originally Posted by PaHumBug

Mine did this the other day for the first time. Hasn't done it since. I got the feeling it was the tranny trying to shift in and out of OD. I gave it gas to make it down shift and it quit. Hasn't done it since. If yours is doing it at 55mph, maybe thats the same thing. My check engine light came on, but went back off the next time I started it. Since then the check engine light has come on every once in a while, but turns off soon after. Does the light need to be lit in order to get a code?

Does the check engine light need to be on in order to get the code out of the computer?

[TXSUT]

Originally Posted by PaHumBug

Does the check engine light need to be on in order to get the code out of the computer?

No.

[trofeo16]

my h2 was doing the same thing. Between 42 and 55 mph the rpm's would be bouncing. Almost like you were slightly revving the motor. No check engine light no codes. Took it to the hummer dealer. They found an entire gm service belletin on the issue. Turns out there is something in the 4l60e tranny that is excentuated by exhaust,intake,maf spacers..etc. I removed all the after market and it went away for the most part. Replaced parts and it came back. If you ask hummer dealer to do a search on bouncing rpms within the service bulletins you will find the article. Hope that helps.