4000 RPM when in park??

[TalonTSiAWDAuto]

I just got a 1995 Eagle Talon TSi AWD w/ Automatic Transmision. When I first start the car it runs great but after driving a while or when its real hot out and the car is hot and I put it in park it will rev to 4000 rpm Then when i put it into Drive or reverse it drops back down. Any idea why??

It started doing it the other day after driving for about 20 minutes. I was on the way to get a new battery so I went by a mechanic first and There was a massive coolant leak due to an old and messed up radiator cap. Fixed that and got the new battery and the car seemed to run just fine, no high RPM at idle. Then today after driving right as I put it into park the RPMs jumped again to about 3500 and would only drop if it was in gear. I shut the car off and went back to work, then several hours later when I was leaving it seemed to be fine again

 

[dot45]

Thinking vacuum leak.. Check for hoses that came off the throttle-body, or cracked hoses.

 

[phunny]

Have you done a boost leak test yet? If not, do it.

 

[TalonTSiAWDAuto]

Sorry for getting back so late. Turns out the air control valve is stuck open. Fixed now runs good...except for I need new ball joints too, fml

 

[sek_phok]

Im sure you can find some ball joints on the local forum.