ok guys here's the deal. While driving home the other day, I eased down on the gas to pass a car, I should note we were traveling uphill. When out of the blue my truck started twitching and what I would say as bogging down. I took it to the shop the next day and mechanic tested the coils, which were all firing. He hooked up the computer and it said Misfire on cylinder #4. He said the plug was bad and it needed replacing. I said ok do it, normally I would have done this myself but time has been lacking. Went the next day and picked up the truck drove less than a block and same thing happened. Long story short, dang thing ain't fixed. I was told that there may be some water in my gas, and I should put a couple bottles of rubbing alcohol in the tank to get rid of it. Still didn't work. Now I'm out of ideas and have no faith in the mechanic. Which leads me to my question. What the hecks wrong, and how do I fix it? Truck is a 97 f250 5.4L 4x4. Thanks for all the help in advance.

 

It would probably be wise to change the COP on the #4 cylinder. I had one that would only miss when the humidity reached a certain level. For about 50 bucks you will most likely fix the problem. If that doesn't fix it, then maybe look at the fuel.

If it is fuel, I would change the fuel filter first and see if that solves your problem.

 

Truck seems to be missing terribly, and gas milage has gone out the door. Gonna replace the fuel filter today, and see if this does anything. Check engine light has started to flash when driving. Will driving it with this happening hurt anything? Is it possible that the coil be bad when they were all checked and seem to be firing? How much trouble is it to replace the COP? Thanks again.

 

If your Check engine light is flashing, it means there is an active miss in the engine. I would change the #4 Cop (assuming you get the same code again 304). The hardest part of changing them is getting at them. You will need a 7mm deep socket. There are more complete directions on the site but the short version is:

-remove the 7mm bolt that holds the cop down,
-then unplug the wire harness from the cop.
-Pull up on the cop and it will pop off (your mechanic just had it off to change the plug).
-Replace the cop, push down to hear the pop and plug in the harness.
-Re-install the bolt and your done.

Cop's are about 40 bucks at autozone!

good luck

 

I have a 97 150 with 2 coil packs not cops ? i had the same problem change the plug and wire . and check the hose clamp going to the heater core it might be leaking coolent on the plug!!!thats what i had .

 

You probably have a 4.6. I think the 4.6 have 2 coil packs with wires. Check your engine.

 

Hi All not to sound stupid but i have the same problem and dont knoe what the cop is

 

The Coil Over Plug, or cop. Replacing it fixed my problem. It is very easy to change but may be a pain to get to depending on which one is bad. Mine was on cylinder 4, but when I had it in the shop the mechanic moved it from 4 to 1 so I could change it myself if it turnrd out to be the problem, which it was. All you need to do is remove the plug connected to the coil and take out a 7.5mm bolt. It should move over enough to get it out from under the fuel rail, and slide straight out.