I have a 2005 F150 XLT with a 5.4 (198,000miles) RWD

A few months back it developed a miss due to bad COP's, typical shuddering around 50-60 MPH.

I pulled off the COPs and while I was in there I pulled my old plugs as well. New Motorcraft SP515 plugs went in with a little nickle anti-seize being careful not to get any near the end of the plug and I put a set of Granatelli COPs on with a little di-electric grease on the inside of the boot. The miss went away and the truck drove like a champ.

I will also note that I replaced the front wheel hub/rotors, front calipers and new pads. I resurfaced the rear rotors, new pads and new E-brake shoes also.

The issue I am having is under light acceleration, or "normal" driving conditions the vehicle has a mild shake which eventually smooths out.

My first assumption was that I did not torque my front wheel hubs correctly or that I messed something up so I took the truck to my local front end/alignment shop for a full inspection and they said everything is great. They also said that they didn't really feel the vibrations that I mentioned. I am used to this truck driving very smooth up until the misfire situation so to me it is quit noticeable. After the front end shop I went to Discount tire cause they mentioned that my rear wheels are bouncing pretty good and that may be what I am noticing. Turns out the tires were out of balance which Discount took care of and rotated my tires while I was there.

The vibration is STILL THERE! No CELs to reference, just an obnoxious vibration.

I tried to isolate the issue by accelerating in 1,2, and in D. The issue occurs regardless of the gear I start off in.

Any opinions or input on this?

 

I recently had a very "slight" vibration at highway speeds... turned out to be the rear drive shaft u-joint in the initial stages of failure.....Have they ever been changed ? 200K miles is overdue.......... That being said, the first think I think of when someone says " vibration UNDER ACCELERATION , is a bad COP. If you can stomp on the throttle at 10 MPH and get the "vibration" I would guess COP... If you have to be running down the road at 60 MPH with medium throttle, that's another story.

 

They are the original U joints, I considered U joints too. I don't feel much play when giving it a shakedown.
The front end shop said that could be an issue as well, they said they would have to pull the driveshaft to confirm though.

I hope it isn't a miss, being that I just spend 400 bucks on parts to fix that issue.

 

It sounds like u joints if there original with nearly 200 I'd change them bud, had a similar problem with my 96 bronco it ended up being a u joint and the double cardan joint

 

I hope that is all it is, for 150 bucks I think I'll go for it.

I was just wondering if I should consider bad fuel injectors, cam phaser, fuel pump, ect... Transmission problem maybe?

I will be pumped if U joints is the issue.

Thanks for the feed back, folks.