Skipping Hummer h2

[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.