2005 F150 XLT 5.4L 3V 4x4, 183,000 gentle miles. I did not post a thread for a problem that I was have for a long time, but finally resolved the problem by reading other threads herein so I thought I would share my resolution. First, you should know that I live in a rural area where there are lots of curvy roads with up & down hills, which contributes to my condition. Symptoms of my problem were as follows: My truck is generally in very good condition and runs nicely... except... when I needed to apply moderate acceleration to go up a hill, my engine would studder, usually only once or twice. I learned to coast a bit longer then accelerate a bit harder to avoid the studder (my wife chose not subscribe to this method herself, adding to her frustration). I changed the fuel filter (twice), and any perceived improvement was probably my hopeful imagination. I think I also changed the transmission filter... with no improvement. I tried driving it with O/D on & off... no improvement. All those nasty spark plugs were change by a braver mechanic. Several times I connected my ODB, trying to record some misfire counts and looking at live data and never getting any DTCs. I would record a small amount of misfires, but they were random across various cylinders and didn't seem to correlate with the studder.

Searching this Forum, someone wrote on a thread closely describing my condition, saying "from my experience"... blah, blah, blah "moderate acceleration" blah, blah, blah "the problem is the COPs (coil over plugs). I replaced all 8 COPs and have not had a recurrence of that condition... even trying to make it happen. Also per everyone's recommendation, I installed OEM "Motorcraft" brand COPs (part # DG-508) made in USA. Thanks for that contribution !!! (I search, but could not find that thread again)
p.s. My wife is borrowing my truck tomorrow... I'm anticipating a good report.

 

I wonder if it was just the boots and springs that needed replacing... glad she's running correctly again for you.

 

I may need to replace my COPS as well. I've done plugs and boots/springs several times but the truck is getting old, these COPS are 17 years old. I am also having a similar misfire as you, can't get any to show up on the scanner.

Did you find a good palce to buy COPs for a good price? Looking to buy 8. I see the prices all over the place especially on EBAY. You can buy a set for $120 or ONE for $60 from advance? Looks like there may be tons of Chinese knock offs out there.

 

I'm usually a local O'Reilly's Auto buyer, and even bought one non-Motorcraft COP there last year to resolve a different obvious cylinder-specific misfire, but can't stomach their price for 8 Motorcraft. I also search the web for "Motorcraft DG-508" and purchased (8) single-bags (see photo below) on eBay from "autopartus" for $19.52 each, description "1 NEW OEM Ignition Coil DG-508 For Ford E-250 Mustang 5.0L". Yes, I have an F-150 but I think DG-508 (as cited in the F-150 Forums) must be used across the Ford line. I do advise that the connection on my new COPs are at a different clock-orientation than my originals, which caused a minor wire-length issue on cylinder 8... but over an 18 year period Ford probably revises them a bit.
Several other sellers have shown them in nice OEM-looking boxes & similarly priced, but the actual Motorcraft name is always pixilated out... why?... too suspicious for me. The COPs received appear to be good quality... time will tell... and we'll soon see if the Forum OEM purist beat me up for my purchase.

 

Studder... Shudder... Fixed
I found the Thread by "chetwynd" that led to my resolution... and the reply by "Ron R" saying...
"From my experience, when gng [going] 45 mph and you give it light acceleration then it starts to feel like a misfire or shudder, sometimes it feels like transmission bucking, that means it's a bad coil. If you accelerate getting on the highway, lets say, and it feels like you ran over a rumble strip, that to me would indicate you need a transmission filter change and fill."
p.s. My wife just returned with my truck... "It's unbelievable... It's like day & night... It's like a new truck".
THANKS Again ! You saved my (40 year) marriage.