Difficult To Start

NOTE: If engine cranks but will not start, see BASIC TESTING article for trouble shooting procedure.

Check fuel pump relay by connecting test light between fuel pump relay connector ignition feed circuit and ground. Turn ignition on. Light should illuminate for 2 seconds. If light does not illuminate for 2 seconds, see FUEL PUMP RELAY under FUEL SYSTEM in SYSTEM & COMPONENT TESTS article. For location of fuel pump test connector, see COMPONENT LOCATIONS in SYSTEM & COMPONENT TESTS article. Check for blown injector fuse.
Check for contaminated fuel.
Check fuel pressure.
Visually inspect injector fuse(s).
Check for faulty ECT sensor and circuit.
Check for faulty IAT sensor and compare readings with ECT sensor.
Check for loss of crank signal to PCM.
Check EGR system.
Check fuel pump relay and circuit.
Check ignition system and grounds.
Check for shorts by spraying plug wires with a fine mist of water.
Remove spark plugs and check for wet plugs, cracks, improper gap, burned electrodes or heavy carbon deposits.
Check for faulty IAC operation (if equipped).
Check for faulty main (or PCM) relay.
Check for faulty TP sensor.
Check for faulty PCV system.
Check for faulty CMP sensor.
Check MAP or MAF sensor.
Check for faulty fuel pump relay.
Check for faulty in-tank fuel pump check valve (if equipped). A faulty in-tank fuel pump check valve will allow fuel to drain back to tank after engine is stopped. To check this condition, turn ignition off, disconnect fuel pressure line at fuel rail and remove filler cap. Using a radiator test pump, apply 15 psi (1.0 kg/cm² ) pressure. If pressure holds for 60 seconds, check valve is okay.
Ensure the installed PROM and/or PCM is correct for that particular vehicle. Check with dealer for latest application information.
Check for improper or worn camshaft.
Check engine compression.
Check for leaking cylinder head gasket.
Check fuel injectors drain down time and circuit.
Check for intake and exhaust manifold leaks.
Check for faulty A/T gear position circuit.