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.
8.EGR valve that is leaking.
10.Throttle position sensor.
11.Manifold absolute pressure sensor
Wednesday, November 17th, 2010 AT 2:26 AM