That system had a flap in an air passage that metered air flow. If the car backfired, the flap could change position relative to the indication that went to the

That system had a flap in an air passage that metered air flow. If the car backfired, the flap could change position relative to the indication that went to the control unit and that threw off the air/fuel mixture. They were also more sensitive to air leaks than a carbureted car.