I’m with the General. I would rent a tester to pull codes. The site has excellent won’t crank and won’t run checklists (for some reason I can’t find them). I’ve seen these retrofits where someone installed the complete wiring harness, instead of modifying first to retain only the wiring systems needs. But, that may not be your issue. Get the codes, if it points towards the TFI module, and your description of the sudden won’t start/run sounds like it, and go to the next step after that. Good luck.