How To Replace the #5 coil for a 2001 Ford Expedition

They eventually wear out. But if you try to replace parts, it will not fix the ongoing problem. You really need to change it to coil suspension. The problem with air ride is the bags will eventually go bad and it cost more to replace them than air bags in the steering wheel. I was lucky. My Expedition had already been changed over

Try here
http://www.obd-codes.com/p0304

Had same problem with 1999 ford ranger i worked on and it was a cracked valve. Might want to preform a compression test on that cylinder. hope this helps and if so Please leave rating on this post and good luck.

either you didn't get your coil packs pushed on all the way or they are faulty

The answer to that, is that what ever coil you
replaced was the wrong one.

You relied on the PO300 codes too much

Take that new coil out,put the old one back
and start walking the new coil ,until you find the
bad one.

There are other ways of testing but not at home
in the driveway

Some coils? how did you know which ones? You need to replace allof the spark plugs and the coils that may be bad. its too expensive to guess, take it to a shop that can tell you which cylinders are misfiring. the coils may not be what the problem is.

Sounds strange for all of that to be happening. The valve covers might need new gaskets. If you have a misfire, it could cause the O2 sensor to have a bad reading. Usually it's only 1 or 2 coils. (I would also replace the associated plug if they change a coil.) You could run it from there and if it doesn't clear up, then replace the O2 sensor at that point. Given the age of the car, getting the O2 sensor out may be a pain because it may be rusted/frozen in. Ford didn't believe in doing a good job putting anti-seize on the O2 sensor heads. Mine stripped when trying to replace an O2 sensor, so rather than have to replace a whole section of exhaust, I went to Midas and had them cut it out and weld in a new piece with a bung for the new O2 sensor.

a very common problem for the 5.4 fords is the coil packs going bad. normally misfires once heated up and under slight load ( in overdrive going up a grade) if the check engine light is on, it can help pinpoint which cylinder is misfiring. if plugs haven't been replaced within last 50-60k miles, plan on replacing plugs, and usually the coil pack that goes bad is one of the rear ones, but impossible to tell without a scan tool. if you don't own one, take it to a shop

go to a parts store and they will let you use their scanner for free. sounds like a cylinder misfiring. The scanner will tell you which one it is.

the order of the park pluggs and coil packs is easy it goes:

driver side passenger side
5 ------ 1
6 ------ 2
7 ------ 3
8 ------ 4

1 through 4 is on the passengers side and 5 though 8 is on the drivers side, and all in order.