I had these codes with a '92 245 with a nearly new O2 sensor. There was excess voltage on the sensor wire (~1.3V) that shouldn't have been there, perhaps due to bleed-over from the heater circuit. Measure your O2 sensor output with the car running and warm and you should see it swing between 0.15-0.85VDC over a second or two (you will have to watch the meter for a few cycles to see if it is operating over the whole range).

My car ran terribly when warmed up, and improved immediately if the O2 sensor was disconnected.

I would also check out your fuel pressure regulator (see if the vacuum line has gas in it or smells strongly of fuel).

Good luck!