Throttle Body Carbon Build Up

[ahenry1129]

I have 2009 Yukon Denali 1500 with V8 engine. Have experienced rough idle/RPM wandering recently. Week ago today very rough idle happened, significant shaking, grinding noise from front left of engine compartment( sounded like pump motor.) Check engine light goes on, "reduced power" warning comes on. Onstar says "no stability control, no anti lock brakes, get car to dealer for service" Can't drive, flatbed to dealer. Monday AM dealer calls. Says problem is carbon build up in throttle body. Says they cleaned up throttle body and problem fixed per bulletin doc #4578A. Yesterday AM, grinding noise heard again, idle goes up and down intermittenly. Back to dealer.

Can't find much info on bulletin #4578A except it relating to old "Pontiac Pursuit" problems. Is this legit service bulletin? Can newer vehicle have carbon build up this early? Do you have any other suggestions as to cause of problem? Dealer says "grinding sound" was Stability control system being activated. Occurs when car at or nearly stopped. Really??

My wife uses this vehicle with our 2 small children. Concerned about safely now during winter especially. Any guidance greatly appreciated. Best regards, New member AL1129

[flyin6]

I have 2009 Yukon Denali 1500 with V8 engine. Have experienced rough idle/RPM wandering recently. Week ago today very rough idle happened, significant shaking, grinding noise from front left of engine compartment( sounded like pump motor.) Check engine light goes on, "reduced power" warning comes on. Onstar says "no stability control, no anti lock brakes, get car to dealer for service" Can't drive, flatbed to dealer. Monday AM dealer calls. Says problem is carbon build up in throttle body. Says they cleaned up throttle body and problem fixed per bulletin doc #4578A. Yesterday AM, grinding noise heard again, idle goes up and down intermittenly. Back to dealer.

Can't find much info on bulletin #4578A except it relating to old "Pontiac Pursuit" problems. Is this legit service bulletin? Can newer vehicle have carbon build up this early? Do you have any other suggestions as to cause of problem? Dealer says "grinding sound" was Stability control system being activated. Occurs when car at or nearly stopped. Really??

My wife uses this vehicle with our 2 small children. Concerned about safely now during winter especially. Any guidance greatly appreciated. Best regards, New member AL1129

 

Ok this is definately different. I can only say that I have now owned three vehicles like yours, two Denalis and my current Escalade. I did note carbon build up in the TB of the Sierra Denali after just 7,000 miles, which I cleaned out. Unfortunately, I am not making the connection with the stability control. It certainly sounds unrelated.

 

THe throttle body contains the IAC or idle air controller which regulates engine idle speed. If that motor malfunctions, then the idle will go to heck in a hand basket, but again, I'm not seeing the connection between that and a suspension component.

 

So if a turn signal bulb burns out does the passenger door start sticking?

Sorry I could not be a little more helpful.

[Cwwhitehead]

I had the exact same problem with my 2009 escalade just before Christmas. Happened during a snow storm and put me in a skid. Dealer said the procedure was to clean the throttle body and if it happened again they would replace it. I told them I wasn't interested in having my family be their guinea pigs but they said their was nothing they could do. Well last night I came close to getting in an accident as I lost all power while passing a transport. I'm now stranded more than 400km from home and all the dealerships are closed today. This is my third Escalade I've owned three Denalis and several GM pick-ups. I've been a loyal GM customer for many, many years. But when your "policies" put my families safety in danger I draw the line. I have purchased my last GM and will make it my mission to make sure everyone hears my story. BTW I'm an Internet marketing executive in the auto industry.