hey guys, I have a 2004 5.4 FX4. Its been running rough and misfiring for over a year now. For the life of me, I cant figure it out. I dont drive it as a daily, so thats why its been this long. But I really need this truck fixed, bad. I mess with it every now and then, but cant seem to figure it out.

Runs really bad, undriveable. Wont stall though. All new motorcraft coils put in 2 years ago. Ran fine. Ten developed the miss almost a year later (only 1000 miles). Ive changed a couple coils again with old ones, no change. Wont throw a code either.

I just went out and tried spraying water all over the engine to see if its a vacuum leak... nothing.

When I disconnect the coils as it runs, some will almost make the engine stall, and some do noting. Ill think I found the problem one, because there will be no change in RPM at all, but then Ill do it more times, and think I hear a slight RPM drop. Theres no clear cut answer. Is it normal for some cylinders to almost make the engine stall when disconnecting the coil, and others theres barely a change?

I just dont know what to do anymore.

If I just had enough and finally brought it to a shop to diagnose, would they be able to tell me exactly where the misfire is, or what the problem is? I dont want them to fix it, I just want to know what cylinder(s) is causing the problem. Or would they just say theyd have to dig deeper to find out? Would the diagnose be specific to tell which cylinder and which part of the ignition is the problem (plugs, coil, wiring, etc)?

Sorry keyboard is broken so it takes forever to write tis out.

Tanks

edit: also If I took the plug out and left the coil on it and ran it, would I be able to tell if its not running right? Of course if its not sparking at all something would be wrong.

 

The first thing to do always is to check the codes. Throwing parts at a modern truck is a waste of money. And, running it with a misfire could ruin the catalytic converters.

 

There are no codes. It wont throw one.

 

There are no codes, it wont throw one.

 

Change the spark plugs. If they have over 60k on them or if they are not Motorcraft, do it. Use the latest Motorcraft plug and be prepared for breakage.

 

I changed the front 4 of the plugs a few years back (it was in the winter, so I was freezing) and never got around to doing the rest. All 4 broke. Its goin to be hell doing the passenger rear. I guess I have to do it, but I'm scared. lol I just don't tink its a plug issue to be honest. Truck only had 80k on it.

 

As I said, more than 60k on the plugs, they need to be replaced.

 

No check engine light? Or no codes checked with a code reader?

 

Nope, nothing.

It will only throw a code if I unplug the coils in hopes to find a change in idle. But then I clear them after. It wont throw a code by itself, just driving around.

I also checked all the injectors with a stethoscope, and they all sound fine.

 

It's probably not misfiring enough to trip the light. You only get a light when you have a hard miss. You have worn out spark plugs or weak coils that intermittently miss. Change all the plugs again.

Do you know the procedure for changing plugs? Crack them loose, solvent down the plug holes, let soak, wiggle them out, Lisle tool if any break, and high temp nickel antiseize on the barrels of the new plugs? Techron in the gas before you do the job can help.

 

And most now recommend removing the plugs while the engine is warm.

 

That's still tough in a 2004, that's the one year they didn't use antiseize at the factory.

 

Yea I know the whole procedure and I still have the Lisle extractor tool. Wish me luck, Ill keep ya updated!

Thanks guys!

 

Man, I tried to remove one today, and only the threaded part of the plug came out. So the entire plug is still in there, just without the treaded bolt part. No porcelin or anything else came out.

How can I get it out now with the Lisle tool? Do I have to try and break the porcelin away or something first?

 

You need a porcelain pusher or something like this:

https://www.f150online.com/forums/ar...ark-plugs.html