[Funracer]

I have to throw in here. Hi Mike. My 83 with lambda behaves a bit differently than your but somehow I feel the issue is related. I have AFR gauge. With O2 sensor plugged in, hesitation on throttle when cold running (open loop). I can watch the AFR cycle between open/close as the O2 sensor heats up and the AFR changes from 13.0 (open) to 14.7 (closed) then back to 13.1 then back to 14.7 then 13.3 etc. After several minutes the O2 sensor will finally be hot enough to stay in closed loop, AFR stays at 14.7and all is good. Driving the car prior to O2 going closed loop is not fun.

None of this occurs if the O2 sensor is unplugged. With no jumping back and forth between open and closed loop the AFR rises smoothly after start and reaches about 14 at warm idle. Driving the car during this warm up period is perfect. No hesitations at all.

I have SSI’s and this puts the Lambda O2 sensor bung further from its heat source and makes it harder to reach signal temperature. For the time being I am driving the car with O2 sensor unplugged like the pre 80 cars.

Best of luck