89 corvette quit running found bad ecm and replaced then the comp was bad replaced so now car idles great but will not take gas runs rough and misses real bad

Start by testing alternator and battery most auto parts store will test for free.

clean throttle body with carb cleaner

Fuel injectors cleaning ! How to Diagnose Test and Clean Dirty Clogged or Bad Fuel Injectors

May be bad gas left in tank. Fill it up and let it run through a couple of times

Sounds like a clogged fuel injector.
Or worse one starting to go bad.
The problem with your car is the computer system readout is analog.
older models have a OBD-1 system and it makes finding the location of a bad injector a lot harder to find.
You could try a after market fuel additive called "sea-foam"
Most Wall-marts carry this product.
Give it a shot,I've done so myself on a VW VR-6 and talk about finicky fuel injectors!.
Worked really well for me,hope it does the same for you.
If I helped any please give me a vote.
Thanks,Gary

i want to give you the right answer but the only thing i think of is the mass air flow sensor.

test an replace your o2 sensors tells the comp what ratios of fuel to air.

on top or near the thermostat housing is a sensor it tells the ECM what to do corvettes run hotter than average cars 210 f i believe, i wish i could chek it hands on in '' REAL TIME" FIND A MECHANIC WITH A SNAP ON SOLIS, DONT SPEND ANY MORE $ ON IT UNTIL IT IS MONITORED IN REAL TIME

replace the coolant temp sensor, not the coolant temp sending unit

bad injector