Misfire after new plugs and coils
 

So, I have a 2005 F-350 5.4 that I did plugs and coils on 3 months ago. Probably 4000 miles on them all, and I definitely domt beat on my vehicles so easy miles. I just had a really bad misfire the other day on the highway, shook the whole truck and lost a TON of power. Could barely get out of it's own way. A little embarrassing on the highway. So, my mind immediately went to the coil packs. So I bought a new ones and put it in (it read cylinder 4, which in my opinion is the worst to get to). Pain in the ass but did it. Started it up, idled fine and thought I was good to go. But on the way down the road she started misfiring again as if the coil wasnt even changed. I dont know what to check or what to look for to do next, but if anyone has advice I'd really appreciate it.

Did you use motorcraft coils? Plugs?

Everything is OEM. It blows my mind

Guy I watch on YouTube had a similar issue. Turned out to be a loose injector. Replaced it and all was good. Something to think about?

Scan it and look at live data or you are just guessing which cylinder and what the actual problem is.
If you already did that, it will be helpful to list the codes to assist in troubleshooting instead of your interpretation of the codes.

Do you mean you pulled codes with a scan tool? If so, what were the codes?

Seems unlikely that you'd suffer that kind of sudden horrible misfire from coils or plugs. Usually that's a intermittent issue unless it's a hard failure, which would have been completely resolved upon replacement.

I'd check for fuel related problems. Injectors maybe, fuel pressure? Fuel filter? Bad fuel?

Just my .02

Yes I did. And it read the P0304 code, just like a normal misfire would. That's why I replaced the coil, and then I just did again incase the coil was bad out of the box. But no, still no change.

The code it read was the P0304 code. The normal misfire on cylinder 4 code

That's what I said too. I've lost coils, plugs, and even had one blow out on my 1999 F250, but even that was this bad. Just shook the whole truck like a rag doll.

Is it possible you had a nest or something in your airbox and the truck ate it? Assuming it was small and soft enough not to bend valves on it's way through, it would have caused some major problems for several revolutions before likely ending up plugged into your cat.

edit: Thinking about it, maybe this happened and now you have a 304 because one of your valves is bent and isn't allowing proper compression.

God I hope not. The truck gets daily driven, so I dont think anything would have time to build a nest in my airbox as it doesnt sit for more than 8 hours at a time. But who knows

SO. After having my truck sitting for awhile and not being able to work on it, I finally tore out the spark plug that was misfiring. Turns out the entire tip was ripped off and completely gone. I've never seen anything like this and cant for the life of me see why. Could it possible be a defective plug? Or is something even worse happening in my engine that I'm not thinking of? I'm speechless!

p.s: Truck runs great after pulling it out and putting a new plug in. I fished around for old remnants of what was left of the plug and but couldnt find anything.
https://cimg4.ibsrv.net/gimg/www.for...58abb1f07a.jpg

Glad you were able to find & resolve the issue. Thanks for posting your findings so if anyone else has the same problem we can check the spark plugs too.

https://cimg6.ibsrv.net/gimg/www.for...827ae3fa8e.jpg
Lorraine, had the same exact issue with my 2007 F350 5.4 3v. Same spark plug ground break off and missing. Attached is my picture- looks almost like yours. Below is my experience, might be of interest to you.

Note that Champion plug ended up possibly being my "savior".

My 2007 5.4v 3v with 120k miles had a misfire on cylinder 5. Pulled over and discovered the plug was loose. Torqued it down, and went on my way. 5,000 miles later, another misfire, same cylinder. Pulled the plug, and the electrode ground had broke off, not a good thing. I replaced the plug with Motorcraft, still had a misfire. Replaced the COP, still had a misfire. I was suspecting cylinder damage from the spark plug electrode ground. I did not have the means for a compression test, so sent the F350 off to the local ford dealer.

I want to note the misfire would occur within one mile of start up, and a definite loss of power immediately upon start up. It also took two seconds to start the truck typically took one second.

Ford dealer had the truck for six weeks trying to find the problem. Yes, six weeks. The replaced the spark plug, COP, fuel injector, and ran a compression test. They could not figure it out, and said I might need to replace the PCM. I said no, and I picked up the truck.

I read 100 pages of threads on the this Modular V8 forum looking for clues. Found where a guy posted carbon issues might cause the plug to not seat right. I bought a scope, and looked at the spark plugs seat, threads, and top of piston. Did not see anything that could help clarify the issue, but the piston did look black.

Bought a Champion plug, it has a very different design than the Motorcraft, More threads, beefier nut, bigger surface where the plug meets the head, and an old traditional electrode ground. Decided it was worth a try.

Removed the Motorcraft plug, and sprayed about 1/3 of a can of carb cleaner into the spark plug hole. Let the cleaner sit for about one minute. STARTED THE TRUCK UP WITH THE SPARK PLUG MISSING, SO WHATEVER CAME LOOSE FROM THE CARB SPRAY CAME HOPEFULLY CAME OUT THE SPARK PLUG HOLE. Had a fire extinguisher handy if needed. Let the truck run for about 30 seconds, and shut it off. I should also note I had the cable to the COP disconnected, to reduce a spark risk to the carb cleaner, fuel going into the cylinder.

Installed the Champion plug. Truck started right up. Went around the block, no loss of power. Checked toe code reader, no codes. Decided to go to Home Depot with the truck, which is over a major mountain, with a speed limit of 65 mph. No power issues, no misfires, no codes.

Carbon build up? Motorcraft plugs not seating well after driving with a loose plug, where a Champion seated better? I don't know- all I know is my truck is back to normal.