Engine Idle Speed Remains High

Check for defective throttle linkage or cable.
Check dashpot or throttle opener (if equipped).
Check idle air control valve (if equipped) and wiring.
Check Throttle Position (TP) sensor and wiring.
Check A/C signal circuit to Engine Control Module (ECM).
Check park/neutral position switch signal to Engine Control Module (ECM).
Check fuel injectors.
Check Engine Control Module (ECM) and wiring.