I have a 91 Civic with a 94 gsr motor, running obd1. I bought this car with the swap, and previous owner saids he had the chip for the ecu custom made for the car. After I put it in a perfectly working chipped p28, it has a lumpy iddle and bogs under3k rpm. If i start the car it idle fines but 10seconds later..idle drops like if the car is goinf to shut off, and starts surging. All ecu's/chip it try, does the same thing. I'm thing its a sensor that was shut off in the previous ecu and not shut off in the new ecu's. No CEL and o2 sensor is not wired up.

 

bump.

also not thrown CEL for o2 snesor cuz its shut off on the ecu.