Hi All !!
Yesterday as I was driving, the Check Engine light came on and started flashing on my 1998 5.4L Expedition.
The engine seemed to have a misfire under load.
Then the check engine light stayed on continiously.
I used a code scanner and came up with code P0304 which is the No. 4 cylinder misfire code.
I looked through the forums and this seems to be a common problem on these engines.
Can anyone advise me with some step by step instructions, on how to remove the #4 COP and replace it, as it seems quite difficult to get too.
Thanks !!
Lou

 

I had to change the cylinder 3 coil pack and that was a pain in the @ss itself. Let me know if you find a link on how to change it.

 

Had similiar problem, I checked the spark plug was cracked... replaced it and reset engine light works fine now

good luck

 

You guys are kidding right? A pain in the Ask? I weigh 400 and changed my 5.4 expy plugs in less then 3 hours.

 

I had to replace #3 and did all spark plugs and rubber boots as well because my mechanic said he had to pull the intake manifold and fuel lines. He's a friend and works CHEAP for me so I know he wasn't ripping me off; it's quite difficult to reach the rear cylinders behind the firewall. My 5.4 STILL misfires even after a new fuel filter (when he pulled the fuel lines he said the fuel was very dirty). Does anyone know the cause of these misfires?

 

TAKING THREE HOURS TO CHANGE SPARK PLUGS IS NOT A PAIN IN THE ***?!?!?!?!?!?!


LMFAOLMAOLMFAO

 

Pull The Fuel Rail And Remove Coil Pack A Buddy Did #4.and All Plugs In 1.5hrs

 

switch the cop from 4 to 1 clear the codes and see if the miss moves to 1 this will tell you what the problem is plug or coil.

 

back to the original post. I have the same problem! I even swapped #4 with number 1 and still had the problem. Changed the plug....still same problem but now I can't get an engine light or code to come out even with a serious misfire goin one almost all the time! Any ideas?

Thanks, Brad

 

Hey guys,
I just had this problem come up on my '02 Expy. again.
It had came up once before and I replaced the fuel filter and it along with the servce engine light went away for about a 2 weeks.

What's the likelyhood that the coil pack is the only problaem?

It's scheduled to go into the dealer tonight (no warranty left ) and if all I had to do was change a coil, I would cancel my appontment.

The error was for cylinder 6.

Get me an answer in a hurry please!

 

I ordered my coil today and will in tomorrow (4/13) I will let you know, though it may not be soon enough.

Brad

 

I installed the new #4 ignition coil today and that solved my problem. $58 and alot of skinned knuckles!

 

invest in some $10 mechanics gloves.... its worth in....

I skinned many knuckles changing my plugs, then got smart..

Later

 

There is other issues that brings up these codes and they not spark related, I have seen this twice in 2 years, just completed a job like this on a 1998 5.4, get ready to dig deep into the pockets, the valves are pulling the stems out of the back of the valve facing, leaving the valves overall longer and the camshaft rocker arms are bottoming out the hydraulic lifters keeping the valves open, hence codes p0301-p0310 engine missfire, run a compression test on that cylinder to see this for sure. you may also have a plugged injector on the back side in the injector filter.
Hope this helps, Broken wire

 

I've been working on mine all week now. New plugs and coils. Fixed it for a few days the it started missing again. compression is good and can't seem to find a problem. Its got to be something easy but can't find it.