i have a 2000 expedition, which has been running rough under load. when you get on the gas, it will chug, and miss. going up hills under load it will also miss. this morning after raining for the first time in almost 200 days. [i'm in so cal] it was ideling rough as well, until it got hot, and things dried off under the hood.
i was thinking it was the coil, but figured i'd pick a few brains of people familiar with this engine, and its quirky habbits
the truck has 77,000 miles on it, and recently had the heads reworked by ford to repair the oil consumption problem it was having.
hopefully that has nothing to do with the current problem.
any tips on this will be greatly appreciated
thanks,
erik

 

after looking into this a bit more, and pulling the codes, there is a p0303 "pending code" for a cylinder 3 misfire.
i am completely new to the arrangement of things on this 4.6 engine.
i am very used to working on my jeeps, but dont mess with the fords i have. after looking for waaay too long for the spark plugs on this thing [damn, i feel stupid saying that] i think i found them under what appears to be individual coils for each plug... is this what it appears to be?

next, i would guess that, that is the componant that is causing the misfire. true?
feedback is appreciated.

 

I can't help much but I'm interested in what you discover. My 2000 F150 4X4 is doing the same thing. I had a check engine light on and the computer coded it as a bad EGR valve; so, I replaced it and the light has gone off. However, the engine still misses when accelerating or when under load. I have yet to get a CEL that diagnoses a bad coil - but I'm guessing that's what it is. I've already replaced the plugs and fuel filter. Good luck.

 

When i ran my codes, i got nothing under regular codes.. it was under "pending" codes.
i have ordered the replacement coil, and will let you know how it works out.
thanks for your interest in this thread.
i am surprised there arent any guru's on this board with any answers.
maybe someone will chime in.... there are plenty of members on this site... someone must have some knowledge on this.

 

I am far from a Guru but I can't afford to pay the ford garage so I have been messing around a bit . If I am not mistaking you have ."coil on Plug" setup.. Coils are expensive. the first thing I would do is pull #3 coil off, Then pull another coil from one that is easy to get at and swap them and see if the next diagnostic code chandes to misfire in the cylinder that you swaped the #3 coil to. If it does Replace coil.. If it still reads "misfife #3" pull that plug Check for loose wires, connections ,and check the #3 injector to make sure it is plugged in all the way.. Hope this helps..

 

make sure your egr ports are clean even though the codes has not been set it will come. the egr valves almost never go bad and the codes do not tell you what sensor to replace they are merely a starting point for diagnosis.

I would bet you have your A/C or heater hose leaking/seaping/condensating above the #3 coil (Very common) and you are either getting an arc from a wet boot or your coil is going south.

Also check all vac hoses especially the ones associated with the PCV.

there are other things to check but this is where I would look first.