2006 Hummer H2

PREM

MEMBER
2006 HUMMER H2
V8
4WD
AUTOMATIC
25,000 MILES

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.

1 Reply

FACTORYJACK

MECHANIC
4,159 POSTS

With as modern a vehicle as you have, if there was a running problem it should be able to give an indication. The grinding sound before a complete stop was the parking pawl ratcheting on the park gear. It looks like the vehicle should still be under warranty, if there is a problem, the dealer needs to identify it and correct it. Unfortunately, there is nothing that I am aware of that matches the symptom. Possible that the backfiring under the hood could be a result of low fuel pressure. If it were a constant condition, it should have some codes set. If it is intermittent, the dealer staff needs to make every attempt to duplicate.