hi, ihave 2006 hummer h2 with 25000 miles.its running and idling rough for more than a year.dealer says there is no any code and everything is fine but its not.sometimes its runnig fine but only once in a while.sometimes when i start after few hours there is backfiring sound coming from inside the engine thats only once in a while.sometimes when idling in cold in the morning engine changing sound.it was running smooth when i bought it but it started idling rough suddenly.i cant figure out the problem.once i put in the park before coming to complete stop and grinding sound came out of the gearbox,i think this should not relate to the problem.can anybody help please thanks.
Nov 2, 2009 at 9:20 PM