Improper Idle/Won't Idle

The engine has a high/low idle speed, engine races, or engine will not idle.



POSSIBLE CAUSE ACTION


MAP sensor hose restricted Repair or replace hose. Re-route if necessary.




Throttle opener operation Check throttle opener operation, adjust if necessary




Idle speed adjusted wrong See ADJUSTMENT PROCEDURES.




Idle Air Control (IAC) solenoid operation Check operation and adjustment




Fuel pressure out of specification Check fuel system pressure




EGR valve stuck See EMISSIONS.