5.3 Idling Problem
 

We have a problem with a 5.3 in a 2000 Chevrolet Truck. When coasting to a traffic light, it will idle up. When put in neutral, it will go to 1,200 rpm. Also, it will delay shifting as if in the tow/haul mode. Also, after sitting for a while, it will temporarily run fine. Any ideas?

Throttle body clean? Sometimes that will make them act weird or could possibly have an intake leak. Some people have issues with the gaskets leaking

Kinda sounds like a vacuum leak....

i probably shouldnt respond but i agree with robert, also do a sweep of the TPS.

Could the gasket idea be why it runs ok after cooling off?


I thought that, but why is the problem inconsistent?

You have stand on the brakes hard when this happens (high idle) when coasting to a stop.

Thanks for trying to help.

tps is most likely sticking i had the same issue just cleaned the throttle body and replaced the sensor works great now