2014 w/random misfires (Roush supercharged)

[Canuck714]

@Brad12 did you ever get it sorted?

I went back and re-read the original post where it was throwing lean condition codes, and it reminded me of another forum member postion lean A/FR codes randomly.
Did it ever throw a P219 for A/FR imbalance? Fuse 27?

Also, I can share some of your pain. I spent the good part of a couple hours a night after work for 4 weeks chasing electrical issues on my truck. I got random Hill Decent Fault, Trailer Brake Control Modual faults, Restarint Control Module cant see signal etc etc.. The dash would light up the ABS and Traction control lights, the gauge mode had the truck stuck on 0's for steering angle, 0 grade, 0 Lean Angle even on a steep grade or the wheels truned full lock. Pulled codes with ForScan and it was all pointing to a bad Body Control Module or Harness issue.

I found and cleaned every body ground (there are lots), disconnected and applied dielectric grease to virtually every harness connector front to back and every plug on PCM, TCM, ECU, BCM, checked every fuse, replaced every relay. Replaced Third Brake light since it is a known Hill Decent fault, replaced harness in headliner since I could see water intrusion from some time in the past... All this did not fix the issue!!! The truck ran and drove fine, but I knew that I would have to take it to the dealer to see what was wrong.

I decided that before I took it in, I would do the Fuse 27 Relocation even though the truck never once quit or would not start. I had a kit in my toolbox already, so figured it would be one thing that the dealer would not have to look at.

BINGO... The minute I turned the key after doing the relocation ever light and buzzer turned off!! WTF...

Sorry for rambling on, but I guess there was an unseen short in the fuse box caused by #27 and it creates "Noise" in the Can-Bus system and creates bad pathways for the modules to communicate with each other. If you have not done 27.. Do it..

 

[Brad12]

@Brad12 did you ever get it sorted?

I went back and re-read the original post where it was throwing lean condition codes, and it reminded me of another forum member postion lean A/FR codes randomly.
Did it ever throw a P219 for A/FR imbalance? Fuse 27?

Also, I can share some of your pain. I spent the good part of a couple hours a night after work for 4 weeks chasing electrical issues on my truck. I got random Hill Decent Fault, Trailer Brake Control Modual faults, Restarint Control Module cant see signal etc etc.. The dash would light up the ABS and Traction control lights, the gauge mode had the truck stuck on 0's for steering angle, 0 grade, 0 Lean Angle even on a steep grade or the wheels truned full lock. Pulled codes with ForScan and it was all pointing to a bad Body Control Module or Harness issue.

I found and cleaned every body ground (there are lots), disconnected and applied dielectric grease to virtually every harness connector front to back and every plug on PCM, TCM, ECU, BCM, checked every fuse, replaced every relay. Replaced Third Brake light since it is a known Hill Decent fault, replaced harness in headliner since I could see water intrusion from some time in the past... All this did not fix the issue!!! The truck ran and drove fine, but I knew that I would have to take it to the dealer to see what was wrong.

I decided that before I took it in, I would do the Fuse 27 Relocation even though the truck never once quit or would not start. I had a kit in my toolbox already, so figured it would be one thing that the dealer would not have to look at.

BINGO... The minute I turned the key after doing the relocation ever light and buzzer turned off!! WTF...

Sorry for rambling on, but I guess there was an unseen short in the fuse box caused by #27 and it creates "Noise" in the Can-Bus system and creates bad pathways for the modules to communicate with each other. If you have not done 27.. Do it..

That sounds like an absolute nightmare, but glad you finally figured it out and I'll bet it's comforting to know all of your electronics are in good working order now! I had Fuse 27 replaced within months of getting my truck back in 2018, but it's probably a good idea to go through it just to make sure that's not the issue. Appreciate the heads up.

I'm getting a P0420 catalytic converter code, so I just got a replacement in the mail a few days ago and I'm going to get it swapped in since it's possible that's what's causing the misfires in cylinders 6 & 8. Fingers crossed.

 

[Brad12]

I got a new (used ~2k miles) driver's side cat put in and that seems to have fixed my misfire issues. My guess is the wiring harness was the main issue and I eventually destroyed the cat because I was forced to drive it while it was misfiring for awhile. So the main problem was the harness, but then the misfires the harness caused then destroyed the cat, which in turn was causing the random misfires on cylinders 6 and/or 8.

I've driven it over 150 miles with some hard pulls on the freeway with no problems, so I think it's finally fixed. Fingers crossed. I appreciate people's help on here... thank you.

 

[Canuck714]

I got a new (used ~2k miles) driver's side cat put in and that seems to have fixed my misfire issues. My guess is the wiring harness was the main issue and I eventually destroyed the cat because I was forced to drive it while it was misfiring for awhile. So the main problem was the harness, but then the misfires the harness caused then destroyed the cat, which in turn was causing the random misfires on cylinders 6 and/or 8.

I've driven it over 150 miles with some hard pulls on the freeway with no problems, so I think it's finally fixed. Fingers crossed. I appreciate people's help on here... thank you.

Glad you got it sorted