Ok, pulled a LS1 5.3 from a 2004 silverado and installed in a 1994 Miata. Had to use an LS6 intake to clear hood and using supposedly 2002 Trans Am injectors . Car is throwing lean codes as both banks are maxed out at 25% adding fuel. I copied the injector PW etc from a 2002 hpt file and saw very little to no change. The car is simply not getting enough fuel. Regulator is a 54 or 58 PSI .
I'm not sure how to get the silverado ECU to give the car enough fuel, as in what table/s will get me more fuel to cylinders.
There does not seem to be any vacuum leaks or undocumented air.