I just picked up a 91 fi 2200 with a bad computer and put in a rebuilt one from carcomputers.com and it runs good but it surges @ idle. I installed a new pcv valve and checked the timing.
they cleaning the thottle body.
check vacuum lines, idle air control sensor, and u might get a away with ajusting the mixture screw
where is the idle air control sensor. I have tryed the screw.
i found the problem it was a faulty ecu car-computers.com replaced it for free