Toshbar

Check spark plug torque.
Sounds dumb, yes, but that's what kept sending a friend's 5.4 3v into limp mode. 25lb-ft.

techrep

iTrader: (1)

Not dumb at all... too bad he won't answer my question so we can help him out...

SCORGE

Not dumb... fuel scent...misfires...limp mode...blow out..lol
Torque is good

BubbaGee

TechRep,
The CEL has never come on but the misfires are so bad now it feels like you are riding a bucking bronco until I let off the gas and get back on it a little harder.

As far as make of spark plugs I don't know. I had a shop do them for me since the factory plugs have the tendency to break in half and drop into the cylinder. I didn't want to deal with that nightmare. The shop that did it said two of the eight broke during removal as it was. Since the plugs are buried so deep, I figure if I'm going to go to the trouble of changing the coils then I'll just do the plugs too.

Aeromech

I've got a fix for you. My truck did the same thing and my plugs had been changed 40k miles ago. This time I changed not only the plugs but the COP insulators and springs too. Problem solved

BubbaGee

To all that are nice enough to try to help me.

I'm at work right now and not able to be on the site all the time. I will check back as much as I can during the day.

Also this truck is my daily driver, so I need to make sure whatever I do during the week needs to be completed quickly.

SCORGE

I have a feeling....if the shop did it...they probably used Autolites or Champions.
I would pull one...check brand and go from there. Just my .02

F150Torqued

Absolutely no disrespect intended and I routinely follow your posts.
But on THIS ONE, may I respectfully disagree - with the first three statements, and qualify my agreement with the fourth. A Mode 06 OBDII test on my 2004 with 220,500 miles reports ZERO misfires on all eight cylinders for the last ten drive cycles. I run this test periodically - and that is the norm. However, I agree misfires have to get pretty bad before a DTC is set. The PCM must have a fairly high count setting before it sets a code.


I change plugs every 50K now. use only Motorcraft SP515's, replace boots each time & use dielectric grease, stretch & clean the coil boot springs & COP spring contact, AND I clean ALL the carbon build-up out of the cyl head spark plug holes below the threads w/solvent soaked rag, and make sure EVERYTHING (including spark plug ceramic) is clean as a hospital operating room and free of greasy finger prints as I go back together. Like @Dirttracker18 says "Sometimes its the little things."


I suffered with the same problem as @BubbaGee for thousands of miles before I finally got it cleared up.


BTW @BubbaGee that 'Bucking' under a load "slaps the heck" out of the plastic chain guides. I contend it is a major cause of their destruction. Try to avoid it until you can remove the misfires.


Good Luck

BubbaGee

To all those that helped.

I was able to stop the misfires by removing the connectors from the coils and cleaning them with electronic connector cleaner and reconnecting. I also cleaned and reapplied dielectric grease to the #2 coil. I plan to clean and reapply grease to all of the coils since #2 coil had little to no grease present when I removed it. I first need to get replacement bolts for the coils since half of them are so rusted I won't be able to reuse them.

Thank you so much for everyone's suggestions.

BubbaGee

Jfrees7

Here is a trick to check the rubber boots on the coils for a fault causing misfire. use regular motor oil, squirt the oil in side the boots of the cylinders that are misfiring, coating the surfave well. pour oil out, replace. One coil pack can cause multiple misfires. so if one of them coated with oil fixes the problem. Just replace the one.. Take note that a spark plug that is worn out can create too much resistance and cause a coil pack to misfire as well.