hey dave im having the same issue with mine ive got cylinder 3 misfire everytime i went and bought an obd got tired of paying 90 dallors per issue ive replaced the plug the injector, and the coil, followed by a new pcm which was covered under warranty thank god! still didnt fix the problem, my symtoms are identical to yours usually misses when im excellerating on the highway or when i put my foot in it, do we have a fix yet?

 

Have they ever done a compression test on your cyl 3 or checked the voltage to the plug/injector? If you're sure there is spark and fuel getting there compression may be to blame.

 

Well it ran worse with new injector once I got into traffic. So I get home and reinstall old injector after swapping it with another one and it still ran rough. So I break down take it to dealer near work who has never seen my truck. Charged me 90 dollars to diagnose it. No codes, but check of #4 cylinder has bad coil pack. They want total of $282 to install new pack plus diag and new pack and labor. Now charging 100$ for about 30 minutes is alittle steep. Me being just a regular wrench head took it out in about 45 minutes and it was a pain the azz but still 100 dollars for labor for this? I will find out in the AM in traffic how it does. BTW I have heard alot of folks saying it is the boot that goes bad not the pack itself....

 

i have a 2006 f150 5.4l 4wd. i replaced one of the injectures and it ran fine for awhile then all of a sudden it started to happen again got it checked said another missfiring then thy did a double check and said cats i got the cats looked at and thy were fine. do u guys think its just the injectures going bad?

 

Hey guys,

I only recently graduated into the Ford Universe, bought my first 04 F150 Lariat about two months ago, love the truck but I am having pretty much the same issue.

Like other posters in this thread, the issue only surfaces when I'm crusing on the highway between 40-55mph, when I'm 3rd gear and I need to accelerate to pass or change lanes the truck seems to shudder a bit, like it's slipping, almost giving the feeling like you're driving over rough road, or a bump, even on flat surface.

My first impression was a trans issue, but after reading around online and on this forum people seem to be leaning more towards a misfire, or torque converter.

Has anyone had this issue and seen it resolved completely? And if so, what'd ya do?!

Thanks.

 

Are you getting any codes? First thing you'll learn is clean the MAF, change the plug, and test the COP. 98% of the time it's a misfire and not a transmission issue.

 

Naw, not getting any codes.

You'd never know there was something wrong until you get up into those speeds I mentioned, low speeds and the first few gears don't do anything, but whenever I need to step on the gas around 55mph there's a hesitation and a vibration before it kicks in.

 

Yours sounds like torque converter lockup issues. Change your transmission fluid with the proper type and amount and see what it does.

 

Thanks VTX,

I'm currently deployed right now (missing my truck dearly). But it's definietely something I'll try once I get back, I just knew this was a recurring issue in my truck and wanted to get some imput so I can get her all fixed up and ready to go as soon as I get back!

 

I have the same issue....1000-2000 rpm, initially when I eased into the gas. Thought it was an overdrive going out as it didn't happen when I took it out of overdrive. Now it happens anytime you ease into the gas 1000-2000 rpm and when you accelerate hard.
The ck engine light comes on and flashes while it is running rough. If you back out of the gas, it will calm down, usually hear a slight "click" and the light will go off...engine goes back to purring along.
Changed fuel filter, no difference. Starting to replace the plugs (replaced them the first time at 100,000 miles) now have 210,000 miles. No oil leaks and it seems to run great other than this. All the plug packs have been replaced at some point. Just read there is really no way to replace the PCV.

Suggestions?