runs better with key off

The engine runs better with the key off. I have to pull the oil pressure switch off to kill the motor.

chry 273 GM tbi conversion

The return fuel pressure is approx 5 psi, I haven't checked pressure on feed side yet. It runs very rich with key on. smooths out some and not loading up with key off. The O2 sensors are not installed yet.

Any Help would be great

Put the O2 sensor in.

Your car isn't running right because it doesn't have all the parts installed.

the gm tbi is your problem those mopar parts dont play well with others lol