I have a 02 Ford F-350 5.4 Super Duty XLT 4X4. A few days ago I began to get a misfire, everyday it seems to be getting worst. In idle you can hear it every so often, but under load, taking off, and when it shifts into over drive it get worst. We put it on a scanner but it shows nothing, the mechanic told me that Fords won't show a misfire or misfire history. I've only driven the truck for about 50 miles so far with the miss and still no engine light, will it ever come on? I'm afraid to keep driving it, I don't want to ruin the engine. Any ideas what to do?

 

How many miles on the spark plugs? How many miles on the truck, and have any of the coils ever been changed?

 

I put a brand new re-manufactured engine in a few years ago, new plugs and fuel injectors, used the old coils. Plugs and injectors have about 17,000 mile on them, have 95,000 original miles on truck. Bought the truck used so I'm not sure if the coils were ever replaced. Seeing I can't get the engine light to come on I can't tell which cylinder to check.

 

I'd take a chance on a full set of cheap Chinese coils. Just don't toss the old ones.

http://www.araparts.com/dg508-style-...-set-of-8.html

This vendor has a forum presence.

 

A decent scan tool that shows live misfires would find it. If its bad as you say a code should soon trip then you'll know what cylinder. Or find a better scan tool..

 

Had it on 2 scanners, even took it to Auto Zone, their scanner wouldn't show any history or misfired info either. Why is Ford the only one that won't show any misfire codes? What would be the next best step to take, pull each coil off and test it that way? I don't think the engine light is ever gonna come on....

 

Not sure if this has anything to do with it or not. I began getting that misfire right after they installed a plow on my truck, do you think it could be any wiring they installed or hooked up to the fuse box?

 

A capable scanner in the hands of a competent person can identify misfiring cylinders in about 5 minutes. Anyone with an Android smartphone or tablet, a BT OBDII adapter, and an inexpensive app can do it. There's nothing wrong with Fords.

It's highly unlikely that the onset of the misfires was anything other than coincidental to the plow installation.

 

Seeing I don't know how long the coils have been in this truck, would I be better off just getting 8 new coils and spark plugs? I'm hoping it's just a bad coil...

 

Coils are expensive unless you get the Chinese ones that the quality is very suspect. It would be better if you got someone with a scan tool capable of reading live data. Autozones scan tool wont do that they only pull set codes. Then just replace the coil that has failed. Until there is a quality part available for a realistic price I wouldn't recommend replacing all the coils. Unless you have deep pockets. Then head over to rock auto and buy the Motorcraft OEM coils..

 

I'd still take a chance on the Araparts coils. They have a decent record, the owner has an account here, and if you don't toss the old coils you have a bunch of spares.

 

I'm gonna call around again and see if I can find a shop in my area with a scanner that can read live data. If all else fails I'll pick up a cheap set of coils to throw in and change the spark plugs as long as I have the coils out and see if that works. Maybe I can find the bad plug that hasn't been firing then I'll just replace the one bad coil with a good one. I can always sell the cheap coils on ebay if I don't use them. I'll keep you posted, thanks for all the help...

 

I called two shops this morning and also stopped at one on my way to town. Every mechanic told me the same thing, Fords will not show a live stream on a scanner and not to hold my breath waiting for the engine light to come on, they usually don't. I guess I'm gonna have to pull them out one by one until I find the bad coil.

 

I'm thinking its going to be a coil as "glc" said.

I had the same problem the truck would begin shaking around 30 mph then again at 45 mph. It turned out to be a weak coil that was not going to throw a code. I could not figure out which one was misfiring so I said screw it and just went with the coils that "glc" also said Araparts.

I payed somewhere around 50-70 dollars for all 8 on ebay and 7 months later they are still working. I don't know how long they will last but I started saving a little money on the side to eventually buy OEM Motorcraft coils.

TL;DR try the Araparts Coils

Edit: Not sure if they are still on ebay but you should be able to buy them off his website

 

I had an obvious misfire on my 05...

I took my truck out an open road where there wasn't any traffic (country road)...
I was able to get it to finally throw a code...just had to get it to start misfiring, then keep my foot in it...turned out to be #8...changed coil and it was good...

FWIW, I have replaced 7 of 8 coils with BWD from Oreilleys...they have been running good for at least 50k miles.. I think they were around $45/each...I believe they have a lifetiime warranty...

Regards!