Improper Engine Idle Speed

1. Electronic Control Module (ECM) grounds.
2. Vacuum hoses.
3. Throttle body and intake manifold for air leaks.
4. Ignition wires.
5. Wiring harnesses and electrical connectors.
6. Restricted pressure sensor line.
7. Throttle opener operation.
8. Idle speed.
9. Idle Speed Control (ISC) solenoid valve operation.
10. Exhaust Gas Recirculation (EGR) stuck.
11. Faulty Electronic Control Module (ECM).