A missfiring cylinder can be caused by.
Worn Plugs, Bad Wires, Bad Coil, Bad Injector, Bad Injector Harness, Vacuum Leaks, the EGR Vavle, The IAC Valve (Idle Air Control), Fuel Pressure.
So, as you can see there are many thing that can cause your problem, I would suggest changing the plugs and wires to begine with since you say they are in need of replacement. I have found that 90% of the time that fixes the problem.
Monday, April 20th, 2009 AT 9:05 PM