High idle after trip on 2001 Silverado

[pwall]

My buddy's 2001 Silverado (5.3l Z71) will idle at 1000rpm after a long trip (>2 hrs or more).

It only does this after a trip. If it's just a short run it's doesn't idle at 1000, but around 750rpm. If he turns off the truck for a couple minutes and restarts, it will return to normal.

Any thoughts?

[Bish]

My buddy's 2001 Silverado (5.3l Z71) will idle at 1000rpm after a long trip (>2 hrs or more).

It only does this after a trip. If it's just a short run it's doesn't idle at 1000, but around 750rpm. If he turns off the truck for a couple minutes and restarts, it will return to normal.

Any thoughts?

 

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Check/clean the IAC (Idle Air Control). Mine started to do the same so I pulled the throttle body, cleaned it, pulled the IAC (top right of TB) and it was filthy dirty. Cleaned and re-installed and the idle returned to normal and has been for about 30K.

 

Also, try to use a Throttle Body Safe cleaner since some TB's are coated with teflon and carb cleaner can damage it.

[pwall]

Thanks! I'll pass this info on to him.

[CapitalTruck]

I'm still trying to figure out what's making my '04 do this very same thing. There is no Idle Air Control on 2004s, at least with the 4.8. This is due to the fact that it has 100 percent electronic throttle (pedal tells computer to open throttle, no cable linkage whatsoever.). If you figure out what is causing this please let me know. I'm thinking about starting to try to test components such as pedal and throttle. Like you, this only happens after a long trip.

 

 

Thanks!  I'll pass this info on to him.

 

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