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 coolant temperature sensor and wiring.
Check air temperature sensor and wiring.
Check Throttle Position Sensor (TPS) and wiring.
Check A/C signal circuit to Electronic Control Module (ECM).
Check park/neutral switch signal to Electronic Control Module (ECM).
Check cold start injector system (if equipped).
Check fuel injectors.
Check Electronic Control Module (ECM) and wiring.