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2011 High Idle = Pushy truck!

dataspng

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dataspng Enthusiast

dataspng

Posted
Posted

2011 Silverado 1500 w/ 5.3, 39K miles, decided this morning to idle at 3000 to 4000 rpm twice, at one stop sign it pushed me into the cross walk until I put in neutral. Engine at temp (12 miles into my commute) No engine light, outside temp 28 degrees, transfer case in Auto due to black ice on road.

 

Idle stayed high until I turned the key off, restarted and ran fine, did it again 5 minutes later. Just drove 100 miles to job site all freeway, temps above freezing now and it’s running fine.

 

No the floor mat was not stuck on the gas pedal and my right foot was on the break trying to keep the truck from going through the stop sign, nowhere near the gas pedal.

 

Truck has always had a bit of rough idle, but nothing like this...

 

I called the dealer and they said unless a check engine light came on or on/off the computer would not have any record of it happening (aka engine revving with foot on brake and speed 0). So unless it did it again or engine light came on they say it would be hard to find.

 

Any ideas? Iced up throttle body? It was cold, clear this morning, no snow or rain. It’s has the off-road package with the GM optional HD Air filter if that makes any difference.

Thanks,

  • Brad D -

 

adamjeeps Enthusiast

adamjeeps

Posted
Posted

Mine will idle high sometimes but only about 750-850 rpm from the normal 500-600.

 

I saw somewhere to try and clean your Mass Air Flow sensor and throttle body.

nickvrebel Senior Enthusiast

nickvrebel

Posted
Posted

I would have the dealer send a tow truck for it. That's too dangerous to be on the road.

 

did the motor accelerate after you were at a stop or did it just never slow down from driving? there is several possibilities that could cause this, but I'm a little about your dealer's service department not showing any concern for your safety. If the dealer gives you the run around contact the GM regional people directly (number in back of your owner's manual) and let them know what is going on.

ujtruck Enthusiast

ujtruck

Posted
Posted

don't listen to that dealer, go somewhere else - ask them to read freeze frame (history) data and tell them to print copy for you

 

now check following values:

GM.ENGINE.CCD1H (Cruise Disenguage1 history)

GM.ENGINE.IDLEDES (Desired Idle Speed)

GM.ENGINE.TP_IANG (TP Indicated Angle)

GM.ENGINE.TAC_MTR_CMD (TAC Motor Command)

 

I think you have Throttle body issue.

CapitalTruck Senior Enthusiast

CapitalTruck

Posted
Posted

don't listen to that dealer, go somewhere else - ask them to read freeze frame (history) data and tell them to print copy for you

 

now check following values:

GM.ENGINE.CCD1H (Cruise Disenguage1 history)

GM.ENGINE.IDLEDES (Desired Idle Speed)

GM.ENGINE.TP_IANG (TP Indicated Angle)

GM.ENGINE.TAC_MTR_CMD (TAC Motor Command)

 

I think you have Throttle body issue.

 

 

Man, that is a serious quality response. That is why I come to this board so often. It's not even my truck, but thanks for such good technical info. You should print this out and take it to the shop.

dataspng Enthusiast

dataspng

Posted
  • Author
Posted

I would have the dealer send a tow truck for it. That's too dangerous to be on the road.

 

did the motor accelerate after you were at a stop or did it just never slow down from driving? there is several possibilities that could cause this, but I'm a little about your dealer's service department not showing any concern for your safety. If the dealer gives you the run around contact the GM regional people directly (number in back of your owner's manual) and let them know what is going on.

 

 

It just never slowed down....... my reaction was to pop it into netural and thats when I noticed it reving. Luckly it was 5:30am and not much traffic. 2nd time it did it was pulling into my companies parking lot. Thats when I let it run... it never did idle down.. I put it in park let it sit at 4000 rpm while I double checked for engine light, carpet or floor mat stuck, gas cap loose... it ran at 4000 rpm until I shut it off. Like a dummy I should of used my cell phone to record it but I didnt think of that at the time.

dataspng Enthusiast

dataspng

Posted
  • Author
Posted

don't listen to that dealer, go somewhere else - ask them to read freeze frame (history) data and tell them to print copy for you

 

now check following values:

GM.ENGINE.CCD1H (Cruise Disenguage1 history)

GM.ENGINE.IDLEDES (Desired Idle Speed)

GM.ENGINE.TP_IANG (TP Indicated Angle)

GM.ENGINE.TAC_MTR_CMD (TAC Motor Command)

 

I think you have Throttle body issue.

 

 

Man, that is a serious quality response. That is why I come to this board so often. It's not even my truck, but thanks for such good technical info. You should print this out and take it to the shop.

 

 

Awesome answer.. CapitalTruck... printing and call dealer now... I figured they had a way to track that stuff, they track everything else :)

dataspng Enthusiast

dataspng

Posted
  • Author
Posted

don't listen to that dealer, go somewhere else - ask them to read freeze frame (history) data and tell them to print copy for you

 

now check following values:

GM.ENGINE.CCD1H (Cruise Disenguage1 history)

GM.ENGINE.IDLEDES (Desired Idle Speed)

GM.ENGINE.TP_IANG (TP Indicated Angle)

GM.ENGINE.TAC_MTR_CMD (TAC Motor Command)

 

I think you have Throttle body issue.

 

 

Thanks UJTruck - perfect info and its what was needed to get the ball rolling on finding out what happened. Its on its way to the dealer for a full scan.

TRCM Enthusiast

TRCM

Posted
Posted

I had that happen to me once in an 86 IROC Z Camaro, except when I realized the problem, I was coming up on stopped traffic and had no place to go @ 60 mph. 4 wheel discs did little slow it down, and just as I was about to put it against the jersy wall, a break traffic gave me just enough room to shoot onto the off ramp where I put it in nuetral and shut her down.

 

The throttle body blade was stuck in the ~ 40% open position. A few minutes with some carb cleaner and she never did it again.

brainpause Enthusiast

brainpause

Posted
Posted

I had that happen to me once in an 86 IROC Z Camaro, except when I realized the problem, I was coming up on stopped traffic and had no place to go @ 60 mph. 4 wheel discs did little slow it down, and just as I was about to put it against the jersy wall, a break traffic gave me just enough room to shoot onto the off ramp where I put it in nuetral and shut her down.

 

The throttle body blade was stuck in the ~ 40% open position. A few minutes with some carb cleaner and she never did it again.

 

 

My dad's '85 Chevy work van did that two or three times, but we could never figured out what caused it. One of those times my gf and I were riding down a country road toward her house, and it took off. We were doing 70 mph on a rough road, and we knew we were approaching the end of the road. At first, she thought I was playing, but when we flew past her driveway, she knew we were in trouble. Standing on the brakes didn't help. I didn't want to blow the engine by throwing it into neutral, but I was running out of options. As we approached the T at the end, the engine calmed down. Scary! Maybe the van and your car had similar issues mechanically.

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