I have a 1997 chevy cavalier with a 2.2L 5 speed manual. The problem with the motor is that at an idle the motor will rev up and down. The tps, iac, cps, along with the fuel presure regulater have been replaced. I sprayed down the intake to check for vacume leaks and there is none. The car has 155000 miles on it. Is there any other things I need to check for that would be causeing this. Please let me know so I can try some idea's that are out there.

there is a hard palstic vacuum line that runs into the cab of the car it could be broken in the car and gm is known to run the hard plastic vacuum lines in the wiring harness one of them could be broken along the line with it running spray EVERYTHING with carb cleaner

try your coil tower housing too, they can arch out causing a number of problems.