I have replaced the air filter...pvc....ccv...pvc hose....and replaced the iac and when I push in clutch to slow or stop the rpm drops from 800 down to 500 like it wants to stall....what else will cause this?
My car has 109000 miles.
My car has a manual transmission.
Did you clean the carbon out of the rest the throttle body? I know these engines well. I suggest taking the throttle body off, removing the IAC (idle air control valve), TPS (throttle position sensor), and all other sensors. Soak the throttle body in cleaner and remove all carbon. Buy a new throttle position sensor and throttle body gasket. If you still have problems, I would have a certified technician perform a ’smoke’ test to look for any more leaks that may be causing the rough idling issue. Valve cover gaskets were also notorious for causing this issue.