I had just got off of work today and started my truck in around 93 degree weather. It started right up with no problems. I pulled up to the edge of the driveway and stopped when it happened. I could feel/hear a misfire, but it wasn't continuous like a cylinder went out. I was at random times. Each time it would shake the truck a little. When I got on the road, it ran perfectly fine, untill i went to slow down and felt it again. I stopped, filled up, and drove home without it happening again.

I know that last summer I had some trouble with a cylinder that would misfire. It went away around mid to late summer and hasn't happened since. I'm thinking it's a coil pack assing up because we've already had to replace 3 a few years ago. It could also be needing a tune up because it's been about 2 years since my last one, because I don't have $800 to get the dealer to do it (yeah, they rape us down here). Anyways, I'm curious as to what it could be.

Modifications: '02 F150 5.4L with 221,000 miles. CAI, 2 catalytic converters removed with a quickflow exhaust (causes an O2 code to be thrown, but that's normal).

 

stop @ your favorite auto parts store, see if they will run codes. ( most do, free)

Yes it might be time for a tune up....In the mean time, Clean the throttle body and make sure the EGR ports are clear, & check for vacuum leaks. Maybe also clean the MAF sensor....last but not least...change the PCV

 

Well my brother in law has a code reader so that's how I know what code it is. I always check it when the light comes on just to make sure, but I'll do the other things mentioned. It hasn't happened again since then, but I'm going to be on the safe side and do that and run some injector cleaner through my engine.

 

you could have gotton a some fuel with a little water in it. but most likely is another coil.