Originally Posted by f-jaun50

My 06 F-150 recently started to misfire, I had the coil packs and spark plugs replaced about 4000 miles ago. I also just replaced my fuel pump module less that 500 miles ago. What could be causing this problem? The misfires are happening in cylinders 4 and 8, so the two most far back ones. Fuel injectors, fuel pump, fuel filter, faulty coils or plugs?