misfire 4,5,6 - 986 Forum - The Community for Porsche Boxster & Cayman Owners

golfglasgow · 11-30-2009, 05:32 AM

1999 boxster with 74000mls.has been misfiring for a while only when you put the foot down.just had major service last week(thought that would cure it but didnt) I changed all the coils on the plugs today but still the same,the plugs were changed last week.You guys got any idea what to try next?

DamageINC123 · 11-30-2009, 04:42 PM

I am having the same issue. I have a 97 with 30,000 miles. Misfire 1&4. I have replaced the MAS and swapped coil packs. I can drive for months with no issues until I wind it out pass 6,000 close to redline. I did the 30,000 mile tune up two years ago and did it again hoping it would fix the issue. I am not that hard on it very often so its not that bid of an issue. However, I would love to know what to do to fix it without keep doing part swaps.

DamageINC123 · 11-30-2009, 04:45 PM

I just read your post again. Since you issue is all on the left bank, try swapping the o2 sensor from one side to the other and see if the problem follows the sensor. Start with the ones behind the cats. If the problem switches side you kno wyou have an o2 sensor issue.

gschotland · 12-01-2009, 03:55 AM

Are you getting any codes?

golfglasgow · 12-02-2009, 01:55 AM

Hi codes are 304, 305 and 306 all cylinder misfire

gschotland · 12-02-2009, 02:38 PM

Have you tried swapping the left and right O2 sensors as an earlier poster below suggested? This is a 20-30 min project at most. Seems like the next logical step.