Super high RPM in neutral or when clutch in

[AKMUNKIE]

I purchased a 1992 Subaru Legacy. It has been running great even though there is no muffler on it. I put it in the shop and replace the valve cover gaskets as they were leaking slightly and also put on the muffler that I was given with the car. It is supposed to be one from a 1992 Legacy. Now that I did a little work my car runs well for the first minute or so or when just warming up. Once it gets ran for a bit it starts revving to 1,900 rpms when I am shifting gears and when I am at a light and either my clutch is in or I just put it in neutral it climbs. It has been up to roughly 4,000 rpms when idling some times. If I rev the engine quick it usually will bring the rpm down to 1,800 rpm and slowly drop from there. Any thoughts or ideas on this. I removed the muffler today and tried running it without it again to see if it was for some weird reason the muffler and it didn't change it.

Any help would be appreciated on this one.

Thank you,
David

[BSOD2600]

cleaned the IAC?
TPS could be going bad, screws moved, and/or need readjusting per the FSM.

[AKMUNKIE]

I have not cleaned the IAC but will do that tomorrow most likely. Need to make sure I have a gasket on hand before I do. Thanks for the thoughts

[Legacy777]

Has it always had the high idle?

Does it have one of these screws on the throttle body?

http://www.main.experiencetherave.com/subaru/images/TB/

If not, I would think someone probably played with the throttle stop screws (which you're not supposed to). They are factory calibrated. If the TPS has not been adjusted/messed with, you could try adjusting the throttle stop screws using the instructions in this third scan.

http://www.main.experiencetherave.com/s ... sting1.jpg
http://www.main.experiencetherave.com/s ... sting2.jpg
http://www.main.experiencetherave.com/s ... sting3.jpg