I have a 2002 Impala that is idling so high that at times you don't need to use the accelerator to reach speeds of 30 miles an hour. I am going to clean the throttle body as well as the fuel injectors this week, but am wondering if anyone has any other ideas.

Thanks

 

Check your throttle cable and peddle. Something could be hanging up and holding it down.

 

I know this thread is a couple of years old, but I did not see my car's symptoms in another thread and I may be able to help someone else. My 2002 Impala w/ 3.8L engine was intermittently idling high and sometimes would lose power briefly when travelling at 60 mph or greater. I checked the throttle position sensor resistance and wiring with an ohmmeter and it checked good. I then connected an ELM327 cable to the car's ODB2 port and to my laptop computer which had scanning software installed ($11 on eBay for both cable and software). The software showed the throttle position sensor reading jumping around at idle, sometimes reaching as much as 20%. Another reading that was erroneous was the MAP sensor which showed around 11 in.Hg with the key on and engine off (although with the engine running it was around 9 or so). Also, once when the loss of power problem had caused the car to quit and not restart, a mechanic was able to get it to run again by re-learning the PCM (computer) (I believe by disconnecting the battery.) These indications pointed to the PCM as being the problem so I found a used one on eBay (approx. $45) and had my mechanic install it. This corrected both the high idle and the loss of power problem. Also, the MAP sensor is now reading correctly.