1990 chevy 2500 computer issues

[tbitrouble]

I purchased a non running 1990. Rebuilt the motor and cant get it to run right. I've found evidence that the computer has been changed or tampered with. It's a 1228747. I've been reading that this model doesn't support knock sensor and ESC. Both of which I have on this motor. I need help figuring out what computer was original to this truck.

I've replaced the distributor, map, TPS, knock, TBI, plus/wires, O2(twice). It seems to run Ok with spout disconnected while cold. When it warms up it Idles high then low then high. With spout connected it misses on idle runs ok at high rpms. seems like when the computer takes over, it craps out!