i put this motor in, and once the car heats up it will not idle, it just bogs down and dies, it drives fine etc. but as soon as i get off the gas it dies. what could be the problem? any help is appreciated.

I have an SI dizzy obd0, injectors, resistor box, etc. the ecu is a PR5, but its throwing the code for automatic ECU, this is the only problem I can think of