I have a 2008 F250 with a 5.4, 120,000 miles and automatic trans. I just bought the truck a few months ago and am it's second owner. Maintenance was done at the dealership where it was bought new. The plugs were changed before I bought the truck and I changed coils trying to stop an odd misfire. I pulled our light weight camper on about a 100 mile round trip to get work done on the camper. We have a few hills around here but they aren't very big, just big enough that the truck had to down shift to pull some of them with the tow/haul button pushed. The problem occurred when I got home and put the truck in reverse to back the camper in to it's spot. The motor shook pretty violently in my opinion but did push the camper where it needed to go. I shut the truck of to unhook and secure the camper and when I restarted the truck it ran good again. It has done this one other time with a smaller trailer but basically the same drive and then backing on to our driveway. I had a mechanic put new exhaust manifolds on a few days ago because both were leaking. While in his shop I asked about my miss fire and he said 8 out of 10 times it is caused by failing VVT/VCT soleniods.I have not pulled anything since new coils and manifolds were done. Sorry this is a longer post but want to give details. Any thoughts or experience with issues like this would be appreciated.

 

Prior to pulling anything, I would see if there are any set, or pending codes.
These can go a long way to pointing you in the right direction.

If you opt for replacement, the VCT solenoids are a "relatively" easy to get to & replace.
If you are replacing them, I would recommend using OEM Motorcraft parts for this, no aftermarket junk & replace the seals too since they are likely fairly old.
Unplug them on the top front of the valve covers on each side & carefully pry the seal out.
They are held in with a torx bit captured screw at the base (might be a T10).
Whatever the size is you can reach it with an extension, BUT!!!!!! make sure you tape the bit in the extension so it doesn't drop out inside the valve cover (that would suck).
Once you have them out, you might find debris on the little screens, or a screen that has fallen out, or even possibly some buildup that is preventing the oil pressure to properly open & close the valve inside, but don't be surprised if they just look normal.
These do ware out & need to be replaced periodically.

Your symptoms could also be failing phasers at your mileage level.
You didn't mention if a full timing job has been done since you are in the "range" of needing it.

 

Thank you for replying to my question. I do not think cam phasers have been replaced if that is what a timing job is these days.
Does it require higher rpms a few times while pulling to make one or the other of these parts fail and then recover and be okay? After replacing both exhaust manifolds this 5.4 is the quietest of the four that I have had. There is no rattle/diesel noise on cold start up or after driving 50 miles. Would failing vct solenoids that don't send enough oil to the phasers cause the phasers to fail? I'm 71 years old and these engines have me baffled. My guess is no matter what, the solenoids should be replaced and if my odd miss never shows up again I will be a happy 5.4 owner. If the odd miss is still present after pulling the camper I will assume much more money needs to be spent.

 

Thank you, the only code was P0442 that I believe was caused by two leaking exhaust manifolds.

 

Just for info, I and some others have a different type oil change to help clean sludge/crud out of engine . This engine has small oil passages and a poor oem oil pump . We do an engine flush either evrey oil change or every other change . Some leave the flush in overnight. I use the cheap walmart motor medic . I try to keep the oil change under 5k miles and I run 5w30 with one quart marvel mystery oil . MMO is a cleaner so it helps clean vcts etc . . Of course at 272k I have done a full oem timing job with a melling oil pump . At the time I replaced the plastic tensioners with the same but if I went back in I would use the old steel ratcheting tensioners with no seal to blow out .
One of the best things to do is drop the oil pan and see if there are any broken plastic guides in there and make sure oil pu is cleaned out . There is more to look at if you do that . There are also some other upgrades if you do a timing job . Getting the timing cover off is a time intensive job so you want to do it right .
No matter what brand of truck all of them have some engine problems .

 

Tepar - that code is an EVAP code & not likely due to the manifolds.
"I do not think cam phasers have been replaced if that is what a timing job is these days."
Well, a full timing job is fairly parts & labor intensive. The MINIMUM parts needed (if I remember all of them) are replacement cam phasers (with new bolts), timing chains & guides, chain tensioners, timing cover gaskets, valve cover gaskets. Then there are the "recommended while you are in that deep" parts like VCT solenoids & gasket seals, upgraded Melling High Volume oil pump, oil pan gasket (dropping the oil pan to clean it out & clean the pickup), water pump, roller followers, & valve lift tensioners.

The "basics" of how the system works are self explanatory like there are 2 cams (1 on top of each head) & 2 chains that go around each cam gear phaser. The job of the phasers is to variably adjust the cam timing based on computer programing / RPM / load / etc..... The phasers are just a spring loaded gear that can be "twisted" on the end of the cam to achieve this. The VCT is an electric valve that controls oil pressure sent to the cam phasers to make adjustments.

When the VCTs get clogged the proper cam control is not possible. Same thing happens if the springs in the phasers wear out or the chain tensioners blow out the seals & no longer keep proper pressure. There are 100 (or more) other variables / failure points / issues, but this is just some basics to help understand.

If you don't have any start up chatter, the engine pulls strong & you don't have many codes pointing to timing issues, you may be looking at something more along the lines of plugs & coil boots.
Random misfires on these engines can sometimes be traced back to cracks in the coil boots allowing the spark to jump to the wall of the spark plug well.
Many code scanners can show you misfire counts.
If any cylinders are higher than the others, you may want to have a look at those boots.

 

Thank you G2IC_Wraith, the truck has had new plugs put in and I put all new Ford coils with boots on it. Have not pulled anything since I put the coils on so with luck maybe it's fixed.

 

Buddy's 05 had 221,000kmi, on it developed a miss, after warm up, traced back to 2 stripped threads on 2 different plugs, on head, dealership thinks they were over tightened when changed.