i have the same problem, it may be the Motronic Control Unit (ecu located in dash above glove box latch) i took readings on my AFM harness and found them to be reading correctly, possibly harness or coolant temp sensor causing car to run rich. where can you get throttle position sensors? AFMs are on ebay all over the place, i think they may be adjustable i just dont know how to adjust them. I would like to replace the MCU and see what happens but i would like some feedback as well. My car seems to be running really really rich, and from what i have learned through experience, the O2 sensor only "trims" the fuel, it doesnt have total control over fuel enrichment. i feel it may be a clogged cat, as my car has over 252K on it, probably original cat, too. keep posting ideas.