I took my 2003 Hummer to the dealer service department today to have the engine looked at. I am experiencing surging or fluctuating rpm's while maintaining a constant speed, in the 40 to 60 mph range. They have not diagnosed the problem yet. RPM surge is about 50,.... small, but significant enough to feel. Even passengers have asked what,s wrong. They can feel the pulsating also.

Has anyone else experienced this, or have an idea??????

Thanks

I took my 2003 Hummer to the dealer service department today to have the engine looked at. I am experiencing surging or fluctuating rpm's while maintaining a constant speed, in the 40 to 60 mph range. They have not diagnosed the problem yet. RPM surge is about 50,.... small, but significant enough to feel. Even passengers have asked what,s wrong. They can feel the pulsating also.

Has anyone else experienced this, or have an idea??????

Thanks

I took my 2003 Hummer to the dealer service department today to have the engine looked at. I am experiencing surging or fluctuating rpm's while maintaining a constant speed, in the 40 to 60 mph range. They have not diagnosed the problem yet. RPM surge is about 50,.... small, but significant enough to feel. Even passengers have asked what,s wrong. They can feel the pulsating also.

Has anyone else experienced this, or have an idea??????

Thanks

How many miles on it?

Might need to clean the intake on the throttle body. Take some carb cleaner spray and clean the inside of the throttle body. Both my Denali and H2 (both have the same engine) experience something similar to what you describe and a quick cleaning of the throttle body clears it up. The Denali will "lope" at idle when you first crank it, but the H2 doesn't when they need some cleaning.

Yes, the mileage is 39,000

Nielsen

i did , and the verdict was dirty throttle body

The throttle body is very sensitive since we have a drive by wire set up. When you have the surge at idle or sit in traffic at idle the computer will shut off the a/c compressor to raise the idle and make the a/c not cool. I just cleaned mine for the second time myself but paid the dealer first.