Hard Starting

If engine cranks but will not start without long cranking, or if engine starts but immediately stalls, check the following:
1. Binding or sticking TPS, or high TPS voltage with throttle closed.
2. High resistance in coolant sensor circuit (see Trouble Code 15).
3. Incorrect fuel pressure or contaminated fuel.
4. Improper EGR operation, leaking, binding or sticking EGR valve.
5. Ignition system malfunction, worn damaged or fouled spark plugs.
6. If problem is primarily during cold weather, check cold start valve operation.
7. Defective in-tank fuel pump check valve allowing fuel to drain back to tank after engine is stopped.
8. On V6-173 (2.8L) if engine starts, then dies, open distributor bypass line. If engine starts and runs properly, replace pickup coil.
9. If engine starts then dies, disconnect Mass Air Flow (MAF) sensor. If engine starts and runs properly, and MAF harness and connections are satisfactory, sensor is defective.