Every once in awhile, I have had a problem where it feels like the car has a lumpy cam and the engine shakes a bit. It doesn't happen too often but probably once a month and then it goes away.

This past weekend I changed the spark plugs. One of the bolts to hold the Coil pack in fell out and I can't find it so the pack isn't bolted down.

I drove the car 40 minutes to work and it was fine. After work, I got the lumpy cam feel and while driving, the Check Engine light blinked three or four times and went off. Then after some freeway driving, the problem went away.

I know that our cars have coil pack problems but this thing goes away and comes back later. How do I fix this?

 

there should be a code stored in the ecm. im thinking most likely a coil. hopefully the code will tell you what cylinder is misfiring and you can replace that one coil.

 

If it doesn't show a specific cylinder misfire on the code you can also do a coilpack check procedure. It is pretty accurate as I had tested my coilpacks before and after replacement with the updated coilpacks.

http://forums.maxima.org/4th-generat...ymptoms-2.html

 

If you have already replaced all coils with updated ones, then could be something else. Coil pack check procedure same as cylinder power balance test? Problem is intermittent so it may pass fine but still have coil problem if you haven't replaced all coils with updated ones. NGK spark plugs?

 

sorry, just read linked thread. Now i know what you mean by coil check.