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.
Mar 6, 2010 at 7:29 PM