I was brought a blank 69 mustang, dakota digital dash, a 5.0 engine and transmission from a 2001 Mountaineer, wiring harness, ecm, fuel pump sending unit and a few other parts. I installed it all, had the ecm reflashed without pats, egr, downstream o2s,. It ran but started throwing codes. It was determined that the 16yr old engine harness had problems. I switched to a carbureted intake and distributor. the tps was adapted and crank sensor and coolant temp sensor retained. Fuel pump relay is now triggered by ign. I was told the ecm would still controll the transmission but it wont shift out of 1st gear. I need serious help now.