93 firebird 3.4l idels at 2000RPM's

I just bought a 93 Firebird from an auction it has a 3.4L engine when I bought the car it was idling high (2000 RPM’s) there are no engine codes, It has a new throttle control valve , throttle position sensor and coolant temperature sensor I checked for vacuum leaks and can not find any . Today I disconnected the battery for 10 min when I reconnected and started the engine was idling at 1000 RPM’s in neutral and 8000 RPM’s in drive when I revved the engine to 3000RPM’s and released the accelerator it would fall to 1500RPM’s for about 15 sec and fall back down to 1000RPM’s when I turned the engine off and started the car it went back to idling at 2000 RPM’s I disconnected the battery and repeated the process and everything worked the same way……any idea why the car wont idle correctly?

well i hope 8000 means 800 or you got bigger problems
any how you need to get a scanner on the car to see what the systems are doing rather than throw parts at it
but if you have the means and must you haven't done the map sensor

Thanks jason yes it's 800 RPM's. I'm not throwing parts at it, the parts I listed where new when I purchased it at auction. I tested the parts so I know they are functioning properly. I also Tested the MAP and it is functioning properly.

Before I went through the expence of having the car scaned I thought I would see if anyone had experienced a simular problem and had a fix for it.