I have an 89 mustang gt with 5.0 ho. When I start the car it will surge at idle, if you try to feather throttle there is no throttle response. It will die then if I start it back up it just starts then dies. As I work on car and keep starting it as the engine builds heat it will start to run better then eventually will run good but with a slight misfire. Car is all stock besides exhaust, and smog system removed. List of things already done: Cleaned IAC, cleaned mas air flow, cleaned throttle body, installed new O2 sensors, plugs, wires, cap, rotor. Recently installed new stock injectors. I set TPS at .94 volts, checked ACT sensor 44k ohm at 64F, Checked ECT sensor 38k at 64F, checked for any vacuum leaks. Tried to pull codes with scan tool and got a 67 code. I am going to try to retrieve codes again. Fuel pressure is around 39 psi with KOEO at 39psi when engine is running. Set timing at 10 BTDC. cleaned salt and pepper connectors. Any ideas would be helpful.