ENGINE SURGE WITH PERFORMANCE TUNE ON H2 HUMMER

[MAC]

Background: I have a 2004 H2 Hummer that I have a performance tune. Mods to vehichle are Volant Cold Air Intake and Flow Master.

Q: When driving between 45 and 55 MPH the vehichle surges. Can this be corrected?

I have re-tuned the vehicle but continue to have the same problem.

Thanks.

Mac

[mikel]

What do you mean by 'surges'?
Do the rpms fluctuate, without any input from the gas pedal?
Or is it running rough?

Have you tried restoring the backup file and seeing if the truck still does the same thing?

Thanks

[MAC]

Thanks for the reply, yes the RPMs fluctuate. It's not quite shift shock but appears as if the engine is not getting enough power within that range. I have not put the factory tune back on, I will try that and see if I am having an unrelated issue to the predator.

[MAC]

I have reflashed to the factory setting and do not have the "surge". I will run the vehicle until it's time to get gas (doesn't take long) and will reflash to the performance and provide an update.
Thanks.

[MAC]

Mike,

Same guy as the Mustang (been deployed). I retuned the H2 with the perfomance tune again and have the same "surge/rpm" issue. Any suggestions?
Thanks,

Mac

[pawngod]

my 08 sierra denali is doing the exact same thing described....it gets a surge about 60mph when going up hill...about 1600rpm when you are just barely giving it a bit more gas to keep the speed the same... the rpm guage fluctuates and feels almost like it's cutting out like a bad plug...other wise runs perfectly

[trofeo16]

I have an 03 H2 and have the same problem. Took the truck to the dealer and there is a service bulletin from GM which states that exhaust, air intakes, larger tires and/or Throttle body spacers will cause the rpms to jump between 44 and 60mph. Customers have reported this happening with trucks that have no tune. All the aftermarlet accessories suppsoedly just enchance the problem. (i think thats GM not fixing a problem). Took the tune out of the truck and removed all the items listed. The problem went away. From the advice of my dealer I put everything back on a inserted corvette servos into trans and problem is hardly noticeable. Hope this helps.

[v6procharged]

my 08 sierra denali is doing the exact same thing described....it gets a surge about 60mph when going up hill...about 1600rpm when you are just barely giving it a bit more gas to keep the speed the same... the rpm guage fluctuates and feels almost like it's cutting out like a bad plug...other wise runs perfectly

my rpms dont fluctuate but mine does the same when im cruisin, mainly up hill and give it a little more gas it just like spudders i guess you could say.