2004 Ford Freestar Misfire


#1

My 2004 Ford Freestar SEL (the 4.2L version, 123,000 miles) is missing. The computer code is P0302 which, from what I can find, indicates a misfire in cylinder 2. I had this same code at 99,000 miles and ended up having the spark plugs and wires replaced around 100K miles. It was all running fine until about a month ago and started misfiring again, badly. I thought it was related to the rain but it is doing it all the time now. At times it gets so bad, I have no power and the computer disengages my A/C (bad at this time of the year). I tried a running a fuel system cleaner that specificially mentioned cleaning the injectors, hoping the problem was simply a clogged injector, to no avail (I know I probably wasted my $10 here). I have a couple of questions:

1. Am I doing damage to the engine or transmission by continuing to drive it? I really don't have a choice but need to know how urgent it is.

2. Does this thing have a traditional distributor cap & rotor or is there an electronic ignition module the plug wires connect to?

3. Where would I find the illusive distributor or ignition module, in theory?

4. Any other theories as to the cause of the misfire (cheapest first)?


#2

Your ignition coil should look like:



You could try replacing the spark plug wire set. But before you do, spray them down with WD-40. That will temporarily (like an hour or so), protect the wires from arcing, and if that solves the misfire, then replace the set. Check them all out to see if there’s any cracking or hardening of the jackets. Also check to make sure one isn’t pinched somewhere.

I’m not sure where the coil is, but you should be able to follow a wire from any of the spark plugs back to it.

Chase


#3

Guess I’m not that great with images. I’ll get it. :slight_smile:


#4

OK, I just purchased the plugs/wires/coil pack. I’ll test/replace this Saturday. Chilton’s finally published a manual for this vehicle and it looks relatively easy to do. They mentioned using cable grease on the connections. Necessary? I want it right the first time.


#5

Not exactly sure what cable grease is, but I'd use dielectric grease.

Chase


#6

Only replaced the coil pack. It had four different visible cracks with rust leaching out from them. Plug wires were all in good shape and since I had the plugs/wires replaced just 22,000 miles ago, I’m sticking with the coil pack fixing the problem.