I have a 2020 F350 w/ the 7.3L gas motor with about 49k miles. I recently starting getting a rough idle at stop lights/signs and eventually got the CEL.
My scan tool said misfire on cyl #4, so after reading posts here tried to get it in to the local Ford dealer here in Reno but they are so badly behind they couldn't even give me an appt to bring it in.
After checking other dealers relatively close I just went ahead and bought a new plug wire from Ford.
Installed new wire but no improvement, so reinstalled the old wire and ended up getting an appt about 1.5 hr drive with another Ford dealer.
They checked it and said the coil, wire, and plug were bad. They said only the coil was covered under the drivetrain warranty and not the wire and plug.
I told them I have a new wire which I gave them so they installed.
They tried to charge me $100 for installing the wire but after I raised hell they relented and only charged me for the plug ($10).
Driving home the 1.5hr drive the truck started misfiring again and the CEL light came on the next morning.with the same cyl #4 misfire.
Questions:

1. Does the powertrain warranty not cover the wires?
2. What else could cause the #4 cyl misfire again after a new coil, wire and plug?
3. how bad is it to drive the truck with a misfiring cylinder?

 

How did your plug look when they pulled the first one out?

 

Good question, I didn't ask.
I'm going back to the dealer tomorrow and will ask.

 

Secondly, hard to believe all 3 failed at the same time,…..are you sure these dudes were techs, and not simply parts changers once they read a code 🤣 Well,…..now that you’ve got the exact same problem just a few miles down the road,…I’d say the answer’s known

If all 3 failed like that,….it would make any tech, worth his weight in salt, wonder why,…and try to find out,…he’ll know ‘something’ caused it,…. the spark system is fairly simplistic on these. It could be something as small as dirty pins on the coil connectors, or back up in the main harness. Even seen the engine heat slightly deform a connector internally, to the point the pins weren’t making good contact in the connector,….granted it was a much older engine.

 

Like already brought up, sounds like they are parts changers not techs.

I’m not a tech either but if it were me my next step would be compression test.

Did the problem go away after they changed the parts or only the CEL they would have reset? If the problem was still present this is starting to look like another lifter/cam failure.

 

with misfiring cylinders ,whether car or truck or atv or motorcycle , the first steps are usually check and or replace plug. swap coil and wire to see if misfire follows. this stuff can be done in the driveway at home. i wont say you wasted time at the dealer but you wasted time at the dealer

 

Nevadasteve, before you go in the dealership today, take a second to compose before you open the door bud,…..i know I’d have to,…after driving 3 hours round trip yesterday,…and had to do that 3 hour trip again today for the exact same thing,…. I’d be smokin’ son,…..chewin’ rusty 16penny nails the whole drive back over there 😎
Granted, yesterday’s 3 hour trip isn’t ‘this’ dealership’s concern,….but, today’s trip surely is.

Hopefully, it’s not the cam/lifter issue like Jay said above,….but if it is,…there’s a faint silver lining,….they put a new engine in your truck. At 49k, it’s in the sweet spot for delam,….PITA to get this done though. Just got my truck/ 7.3L,…been babying it big time,…only has roughly 130 miles on it,…bet that dude ain’t went over 2300 rpm yet 😀

Jay, wanted to say thanks again for talking with me on the phone a couple weeks back about the Carli suspension,…..two days and a wake up before mine goes on 😎 Heavily considered One Up Off-road suspension, but decide to go with Carli because my local guys are familiar with their stuff,….and I didn’t want them experimenting on my truck with unfamiliar gear 🤣🤣🤣 Definitely see the expertise One Up Off-road has put into their gear,…impressive. Jay knows what he’s talking about guys, good source for sure.

Nevadasteve,…yer a grown man bud, and I don’t presume to tell you what to do, but,…...I wouldn’t go in there loaded for bear today bud,…..but,………..I’d definitely get right up in em’,…..with a big smile on my face the whole time 😁 Anything outside that, and they’d have grounds to label you,…..

 

How’d it go at the dealership yesterday Nevadasteve?

Kept sitting here thinking yesterday, “how the heck can all 3 go bad at the same time”,…in a past life, I was a Union Electrician, before moving into Construction Management,…and before that, I was a Sonar Tech (electronics tech) in the Navy, and before that, my high school was a technical high school with 3 years of electronics tech,…….. thus, I just had to look at this again to see if I was missing something,….. I even went out to the truck and popped my hood for a look.

I don’t see it,….full stop. So now wondering what they came back with,…please let us know.

 

Update:
Finally made the trip back out to the Ford dealer and they ended up doing a compression check and leak down check of which the motor failed both.
They took the intake and 1-4 bank head off and what should appear......a failed cam/lifter, a stuck intake valve, scored cylinder, and lots of shiny stuff in the oil.
Ford approved a new long block so I guess that's the best outcome after screwing around with several drives out into the desert of NV.

Hutchinson, thanks for the advice....which is what I did. I kept telling myself that they are my best hope for getting a positive resolution so don't kill the messenger!

My only concern is that I had the fuse box lid not installed properly from the factory and there is some evidence of water. Being NV it doesn't rain much but not sure if I should proceed with the replacement.
They want about $700 to replace the box. Seems like this should be a recall or at least covered by Ford.

 

https://static.nhtsa.gov/odi/tsbs/20...80333-0001.pdf

 

Yeap, that’s the TSB I was looking for just now for NevedaSteve,….thanks morehouse7.

I had previously heard of this J-box issue, so I did a quick scan this morning on 2023 TSB’s (under the 62 manufacturer communications on NHTSA),…may have overlooked it, but, didn’t see one in there. Just learned of this site from one of my other posts,…..thanks for hooking me up fellars.

Engine replacement,….PITA,….but, faint silver lining 😎

From what I see on morehouse7’s attached TSB, this swap looks puuuurty easy. And, from what I understand, the new J-box is beefier than the original,…grey colored, instead of black,….and Ford techs are accounted to charge 0.6 hours for this swap,…..that’s simply what I’ve previously read on some of these posts,…could be incorrect. May want to consider doing this one yerself,……if so inclined - $700 was parts and labor? Wonder what just the box costs,….and if you can get one online cheaper,…if you wanna DIY.

If you lived near me, I’d help you slap this one in, fairly quick.

They say how long to get you back down the road, running again?

 

Sux to hear about your engine failure on your F250. I'm surprised you didn't hear any tapping/knocking noise. Is Ford installing a new or rebuilt long block? I've been hearing of scored cylinders, but not sure what's causing this. Where there any other cylinders scored besides the one with the failed lifter/cam lobe?

 

FishOnOne the dealer said a new long block but I will inquire specifically as Ford may be remanning at the factory I suppose.

There was some faint knocking only when under moderate/hard acceleration, but while cruising sounded fine. However, recently while first start up and idling it sounded almost like a serp belt idler pulley or tensioner was making noise but I hadn't pulled the belt to check yet. I suppose that was coming from #4 cyl too.

They said only cyl #4 was f'ed up but I would expect with all the nice shiny metal flake in the oil the rest of the motor was following suit especially the rod/crank bearings.

Hutchinson, I don't have an ETA yet on the motor but should have sometime today. I appreciate the advice on the fuse box I may just do the swap myself. the $700 was for parts ($450ish) and labor ($250ish).

I suppose this is the best result to expect with a new long block so I'm happy as long as there are not nickel and dime crap that's not covered.

I assume they will use all the old plug wires (along with all the intake/injectors, etc.) so I'll replace all the old wires since they are from the 2020 early build.

 

Did a quick search, found part number LC3Z-14A068-A (and LC3Z-14A068-B) in the TSB.

From what I saw on a few sites, the A is for Diesel engines,….the B is for gas versions - circa $214 for the B

 

Funny you mention that. I was digging around today looking at/for upfitter connections, and the grey pass fuse box lid was not fastened and up about a half inch in front.
I've been in heavy rain a couple times since new, hope it doesn't affect anything. I also tried to remove that lid to look inside. What is the
trick to get that lid out? I tried all different angles, no go really.