I bought my 2008 GMC Sierra new 2 years ago, and recently i've noticed the engine loping when at idle. I'm a diesel mechanic for the military so I went through the basics, replaced the air filter, no change. Then I moved on to the fuel filter, but on further investigation I found out that the new models use an internal fuel filter in the pump, so its a non-replaceable filter, according to Hayes. So now, i'm almost certain its the spark plugs, but seeing as i've only had the vehicle for two years, that shouldn't be the problem, which is the reason why I'm here, to verify if i should replace them. Thanks.
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2008 GMC Sierra V6 engine lopes?
- Thread starter pyro
- Start date
Molson02536
New member
I bought my 2008 GMC Sierra new 2 years ago, and recently i've noticed the engine loping when at idle. I'm a diesel mechanic for the military so I went through the basics, replaced the air filter, no change. Then I moved on to the fuel filter, but on further investigation I found out that the new models use an internal fuel filter in the pump, so its a non-replaceable filter, according to Hayes. So now, i'm almost certain its the spark plugs, but seeing as i've only had the vehicle for two years, that shouldn't be the problem, which is the reason why I'm here, to verify if i should replace them. Thanks.
Here is a shot in the dark, check your fuel pressure and try swapping out the fuel pump relay with another relay like the A/C relay and see if that helps your loping problem. I don't think your timing is off or your Service engine light would have gone on. Keep us all posted, be glad to know you got your Sierra running 100% again soon friend.