[12gauge]

I have little to no backpressure so my o2 sensor gives to lean a reading and kicks the ecm(1993 CHEV - OBD1) into limp mode. My 5.7L is getting about 7 mpg. I want to trick the ECM by sending the correct voltage from the o2 sensor (make my own O2 simulator) to fix my problem rather than having to add backpressure. I know there are simulators for sale but nothing for my model year. If you have any ideas on how to do this, I would certainly like to hear them.

My truck originally had only one O2 sensor, it was just below the drivers side manifold(1 wire). The drivers side header now has it in the collector.