2000 camaro 3.8 problem when car first comes up to temp and cursing let of the gas the Rpms drop to about 300 like the car wants to stall but never does also happens after car has sat and hot start and driving goes away after it does it couple times only happens around 35 mph and 25 mph. Happened before and after rebuilt tranny no codes drive with scanner hooked up all sensors seem to be working good new EGr maf sensor no vaccum leaks fuel trims are perfect intake manifold has been done car dosent leak or loose any fluid stumped please help

 

Sounds somewhat similar to how my 98 Z/28 was behaving when the TPS was dead/dying. High and low fluctuating RPM's.

 

I thought the same thing only thing is I watch the tps when it does it and it stays steady and there is no other drivability issues and unfortunately the 3.8 you have to replace the whole throttle body to change to a and that's 300 bucks for a new one I could pull one from junkyard and swap and see if it goes away other then that could just wait till it's gone completely or throws a code but been this way over 7 months now maybe a pcm issue?