I’ve had an issue recently with my 2008 Impala where it revs by itself randomly so once in gear it’ll go by itself randomly.

Brought it to a local shop and they replaced the throttle body sensor and accelerator pedal with after market parts. I believe they cleaned the throttle body as well. Drove it around for 0.5 hour and got a reduced a reduced engine power warning. Gotten those before and just replaced the accelerator pedal myself. After being there for weeks they couldn’t find anything pinned out some wires as well. They ended up swapping parts for factory parts.

Got it back and drove it for a little bit, no issue. I was braking going through a turn going down hill and I felt the car kind of accelerate a little. I imagine it revved just a little bit by itself. Drive it again and upon starting it up it’s revving at like 1.5-2k rpm so once I put it in gear it’s going to go by itself alittle.

I wasn’t that satisfied with how long the small shop took so I took it to the Chevy dealer. They did an idle relearn and reprogrammed the ecm. They drove it around a little quickly and thought it was fine.

I drove it around 4-5 times and on the fifth time it started doing it around. Started it up and started revving 1.5-2k again.

here’s a video of if revving by itself in each gear. Any ideas on what to do? With the cost of vehicles I can’t afford to buy a decent one.

You Tube

 

i know this thread is from january, but i had this same exact issue with my 2001 impala.(3.4) i fixed it a few years ago. it's one of two things, and in my case a combination of both. idle air control valve and throttle posistion sensor. both items are not expensive and are actually easy to replace.

 

I have been having the same issue was wondering if you ever fixed it and what was the issue