Check the fuel pressure to rule out the fuel pump if okay.
Engine running rough or misfiring can be cause by the following:
1. Defective spark plug.
2. Inadequate spark/coil, defective spark plug wire.
3. Lack of compression
4. False air leakage.
5. Faulty fuel injectors.
6. Insufficient fuel pressure.
7. Contaminated fuel.
8. EGR valve that is leaking.
9. Oxygen sensors.
Wednesday, February 17th, 2010 AT 5:53 AM