[exalteduser]

my 97 lumina has a bad missfire, cyl 3. code was p0303, so i changed all the spark plugs they were all white except #3 was black and oily. i also change the coil pack and the spark plug wire to #3. still no luck. some suggestions i stumbled across were the egr valve, oxy sens, low fuel pressure, bad injectoror valve or compression problems. i was wondering if anybody knew which of those would be more likely the cause or if some one else has had this problem had a suggestion. any help would be great, and by the way this happened once last year but quit and it restarted about 4 days ago.