have a 92 si hatch, blew the motor, so I got a 98 d16y7 basically free, swapped in the motor, changed the alternator and the distributor(using the harness off the old motor) tried to use the old injectors, but they wouldnt fit, but my biggest problem is the car runs, but it wont rev above 1800 rpms.......

 

Sounds like an ECU issue. What are you running?

 

stock si ecu

 

did you get a conversion from obd1->obd2? if not, your using obd2 stuff on obd1 ecu, which may cause it to go into limp mode......don't take that as fact till you get another opinion, but thats my guess.