IIRC the '92+22re's fuel injectors have a different impedance and wont work with the pre '92 ecu's. This isn't a real issue, just swap over the the '94 engine(block and head), but use all of the '91's electronics.

More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed