mastatrasta

I have a 93 lt1/t56 car, runs fine closed loop but runs like crap open loop (idles fine but if I get on it it doesn't want to go), I originally bought the car with a blown head gasket and swapped in a 92 corvette lt1 (low miles motor put new gaskets and rings in it), put on a NOS throttle body with new iac and tps (mine was corroded in the lower coolant area), put a new iat sensor and rebuilt ford injectors with a new fpr and filter. Has a new acdelco optispark plugs and wires. Also put a new luk clutch and flywheel.

I'd like to not have to let it warm up before I drive it but I can't figure out what's causing the issue.

Does anyone know if they released a new PROM for these cars or something?

I have checked the car with a scanner on an overnight cold start and everything looked good (map sensor was good iac position was good and iat and cts all read fine)

I have also unpluged the air pump to make sure it's not causing the issue and it ran the same.

The car has to sit atleast 5 hours or so for it to have the problem and it's usually closed loop in 2 minutes or less and running fine
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I don't want to start throwing a bunch of parts at it if there is something in the computer causing the issue, the car was used and abused before I got it.