I solved it by adding BMR motor mounts and lowering the motor 1/4”. Never had any problems after that. The motor movement is what caused the issue and the mounts fixed that with only a little NVH added
I sold my car in November of 19 but I know it is still on there. I also have one on my Wrangler JL and i love it especially getting the 37's to move. It feels more alive even though there is no HP gain.
Id consider it if it has a 10R80 and not base model, at least leather and digital dash
Oh I noticed the NT555R's int he rear were at the end of their lives. So I put new NT555R's on the rear. Nothing like dropping another $700 on a car you are looking to sell :)
The new controllers from Fore do not require and you should not use solder. So check that first. Looks like a bad ground or you could have a cut in your power cable that is grounding. Had a friend with the same issue and it was a mixture of bad gound and poor power connection to the FC3 controller.
Do this to see if the gate is causing issues. Also, you said stock headers so I am assuming you have cats still right? Your STFT are in the low .9's. What fuels system or injectors are you using? Your trims fall off right where you start seeing knock, so it could be/most likely is a fueling...
Want to go auto and stay in the mustang family? Maybe we can work out a trade? https://www.mustang6g.com/forums/threads/850-whp-premium-mustang-gt.126101/