Own a 1990 f150 4x4 with a 302 v8. The truck when I am stopping and I put in the clutch the rpm's rise to 2500 and won't drop . I don't know what is going on with it and I was wondering if something was wrong.

 

Check the IACV and also check for vacuum leaks also check the tps for continuity and also make sure Ur o2 sensor is in working order sometimes if the 02 sensor isn't reading right the computer will get confused thinking the engine is cold and raise the RPMs.