Truck has been acting up lately. 07 with right around 80,000 miles. Once the truck is warmed up and in overdrive at low rpm's, it feels like a cylinder is misfiring and jerks a little bit. Brought it to the shop that ive always used and trusted. They looked at it and drove, said it was a cylinder misfiring but that was about all they could say about. They think its a coil pack but said they cant be certain what it is until a check engine light comes on so they can get the codes from it. Any ideas would help.

 

Is this a 5.4L? Have you changed plugs(use di-electric grease), fuel filter, air filter. Check your FPDM above the spare tire for excessive corrosion/holes also.

 

Sorry forgot to put it was the 5.4L. They said it is a coil thats making it misfire but cant identify the problem exactly till it throws codes. Would seem like I should just replace the coil packs then.

 

My 07 did the same thing at 95,000 miles. I replaced the plugs since it was to about time anyway. That solved the problem.

 

Same thing with me and it was a coil. And u dont have to have an engine light on to throw codes. A shop found mine on cylinder 4 with no engine light using a computer. Replaced the coil and wala problem fixed then i changed the plugs a week later. Runs amazingly

 

My 2005 did the same thing at around 105,000 miles. My mechanic that changed the spark plugs said it was more than likely caused by the spark plugs. Haven't had an issue since the change. Changed the plugs, fuel filter, and air filter. My $.02

 

He said he hooked it up to get codes but it hadnt thrown any codes. So he isnt sure what cylinder it is that has a bad coil but that it definitely is a coil. Dont really want to replace all them just to fix one. Dont have the money to throw around like that.

 

Ok i think i know how u can get your engine light to come on. When does your truck do the sputtering the most? Whatever it is next time it starts to sputter (if you are safely able to) push the pedal to the floor. And it should start to do it a lot more and yes it'll sound horrible but thats how my engine light came on one time. If what i think is going to happen you wont get much acceleration. Just be careful.
And again this depends on how bad you want your light to come on so u can find what coil is bad.

 

Why don't you go buy one coil, and start swapping it around on every cylinder... Coils are about 45 to 50 bucks a piece on these motors... It is actually a better deal, especially if it is more then one coil, to just buy all 8 in a package deal for around or under $300....

If that doesn't fix your misfire, then it could be a bare or broken wire (like I had) with no code or a bad plug....
When I had a misfire, it turned out to be the hot wire on the cylinder 2 coil. Some mechanic before I bought it soldered a test lead onto that wire and then left it there exposed with almost 2 inches of stranded copper arching all over the place. After I fixed the wire it ended up damaging my coil, so I replaced that too, all in the autozone parking lot. I haven't had an issue since... BTW this all happened the day I bought the truck.

If you let this misfire persist, it will melt down one of your catalytic converters eventually....

 

45-50 bucks? Ive seen about 140-150 a piece. if it was 50 a piece I would replace all of them.