2007 5.7 Hemi in 73 Plymouth Duster (pedal cuts out)


I recently put a 2007 Chrysler Aspen 5.7 Hemi in my 73 Plymouth Duster, with a Durango 545 RFE transmission (4x4 but running it as RWD only), 8 3/4 rear end. It has the Digital instrument cluster outta the Aspen, and a fly by wire pedal.
Ive had an issue for months that I cant seem to solve.
When Im holding constant acceleration at higher speeds my accelerator pedal cuts off, and I can no longer accelerate (total loss of pedal). Its also not giving me a speed reading. The only way to get it working again is by turning car off, then back on. If Im driving the car and only gas it for a few seconds at a time I can normally avoid this issue (no constant acceleration).

*I have tried 2 new accelerator pedals, changed transmission speed sensor, and made a whole new wire harness. I still have the issue.

I was told that this issue could be caused by the fact I dont have the ABS hooked up in the vehicle. That I also need the speed sensors off the ABS system.

Has anyone had this issue? Or might know whats going on? Thank you!
You should have the OBD conector in that harness scan it with a scan tool post the codes , normally if it sees gas and brake signals at the same time is one issue ?