Engine Idle Speed remains High

Check for defective throttle linkage or cable.
Check dashpot or throttle opener (if equipped).
Check idle-up vacuum switching valve (if equipped) and wiring.
Check idle air control valve (if equipped) and wiring.
Check Throttle Position Sensor (TPS) and wiring.
Check A/C signal circuit to Engine Control Module (ECM).
Check park/neutral position switch signal to Engine Control Module (ECM).
Check cold start injector system (if equipped).
Check fuel injectors.
Check Engine Control Module (ECM) and wiring.