What is your question?
The car has 43,000 miles on it, and runs very well most of the time. After taking an 800mi. road trip for Thanksgiving, I returned home and the next day, the car started to lag and the CEL illuminated. Hooked up my OBDII scanner and it read a misfire on cyls. 4 and 5 (opposite banks.) After letting the car sit for half an hour, the problem disappeared and it drove great. Fast forward a month and another long road trip later, the car developed another miss but without the CEL illuminating. I filled up with fresh gas (thought it might be bad gas during the trip,) added some Techron fuel system cleaner, changed my fuel filter and cleaned the MAF sensor. Car ran great again for a few weeks, passed state emissions test just fine. Today developed another miss (car was bogging down under throttle, bucking a little, and exhaust smelled somewhat burnt (could a lean condition present under a misfire?)(no check engine light.) Ran KOER and KOEO tests through OBD port, popped a code for CYL. 4 misfire. Pulled the coil on plug and inspected the boot, it was in great shape and the plug well was free of any debris, water or coolant. I applied di-electric grease to the boot ends and re-installed COP. Car ran just fine again.
I'm wondering what this could possibly be..it seems to happen after the car has sat for a day or more, and after periods of rain or moist air. It is winter now and temps. are 40F and below. I could detect no intrusion of rainwater in the engine bay and the plugs are all dry. I would rather not go replacing coil plugs unless totally necessary, because they are kind of pricy and Ford mentioned a majority of them get returned in perfect order.
