Rough Idling 07 yukon Denali.. Come on in

[dogger37]

Ok gang,
I have a rough idle in my denali that seems to keep getting worse. I've had it to the dealer 2 times now. The first they suckered me in to getting a fuel system cleaning that I thought was what they consider a "top end cleaning". They basically just dumped fuel cleaner in the tank and sprayed the thottle body with cleaner. I thought they were going to pull each injector and line and clean them. Second time back they say they have no idea what it is and want to now pull the injectors and lines to inspect and clean them. I said that I am not paying and they agreed to cover the expense. Im at 82,000 with a GMPP extended warranty. Has anyone else noticed a rough idle? If so have you found the cause?

Thanks in advance,
Donny

 

[73shark]

Disconnected spark plug wire.

 

[dogger37]

no dice. I changed the plugs and checked the wires

 

[Ajay]

Donny,

Take your truck to a different shop and have it put on a diagnostic tester. Should be an easy issue to target and fix.

 

[mikeb33]

If it is a plug or wire, it would be missing on a specific cylinder, and set a code for it. Have you had a check engine light come on?

A proper fuel injector cleaning is hooking up a machine to the fuel rail on the engine. They block off the return to the tank and this machine puts injector cleaner in and the engine runs off of that. It is far stronger than any concentration you can pour into the tank. They run the engine for about 5 minutes, rev it up a bit, and then disconnect.

 

[ezstriper]

Do you have a cylinder management ?if so seen one that the lifter went bad(they bleed off to deactivate the cylinders) and if they do it at idle cause a rough idle..tuff to find...Rob