heres what i would do:
check fuel pressure.
do an injector balance test.
what are your pulse widths and LTFT?
2 possible scenarios-
one: you have a massive vacuum leak, i would check around the IC on the snout side of the blower.
two: you have high fuel pressure and the computer is overcompensating and making it run lean- or possibly a leaky injector getting overcompensated.
post your LTFT and pulse width and itll narrow down which way the computer is compensating.
