over reving of engine

Sounds like you may have a vacuum leak somewhere.

I cannot find a vac leak. It seems like when I backup sometimes the rpms redlines. I turn the engine off and I grab the cable before it goes into the throttle body and snap it back a couple times and rpms drop to around 1500. Normal is about 750. i have been driving now for a couple days. Will not drop from 1500.Sometimes rpms goes up to 2000-2500. then drops back to 1500 without touching anything. Car drives find and has not redline again