Wednesday, November 29, 2006

Code P0302 causing misfire for 1996 Pontiac Grand Am with 2.4L engine


Four days ago, my Grand Am started misfiring and when I scanned it, I got code P0302 cylinder #2 misfire. Using your earlier advice, I removed the top valve cover and run my own plug wires and switched #2 cylinder with #3 cylinder but the misfire stayed at #2. Switching the ignition coils also made no difference. Because the vacuum hose going to the fuel regulator was wet, I changed the fuel regulator and again made no difference. All the compression readings were over 200 psi and I am losing my wits on what to do next. Your help will be much appreciated.

ATS Adviser:

Since you got the valve top cover out, you might as well do a balance injector test as described in ATS Course. Another quick way to do this is to switch injector #2 to another injector like #4. Then make sure the engine is warmed enough and see if the misfiring will remain in #2 cylinder. If it moves to cylinder #4, you know pretty well that the problem is the injector.

ATS tip:

The fuel regulator although defective in your case, will not cause misfiring. It will make your engine fuel mixture to flood or rich though and cause hard long starts.


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