Incorrect Idle at Engine Start-up

Check for defective throttle linkage or cable.
Check throttle opener or dashpot (if equipped).
Check idle-up vacuum switching valve (if equipped) and wiring.
Check idle air control valve (if equipped) and wiring.
Check Engine Control Module (ECM) 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).
Ensure dipstick and oil filler cap are properly seated.