Been driving my car around for a few days and I have noticed a weird idle problem. Some times when I come to a stop and push the clutch in the car will idle at 1500 rpms. If I rev the engine a couple times it will come down to the normal 900 rpms. It doesn't do it every time but its consistent. It also wont do it on start up just when I come to a stop. Any ideas? Is the idle motor adjustable? I had cleaned it when I put the car together.
Info on the car
1986 Iroc
406
TPIS Big mouth intake setup
52mm Throttle body
Speed density computer with Howell harness
T56

 

My car has been doing the same exact thing except I have an automatic. Did you ever figure out what was causing the issue? I've already replaced my ignition module, idle air control valve, egr valve, egr solenoid.