Rocky, I just had my '97 C230 diagnosed last week and it came up with the same problem. My independent tech advised me to try some fuel additive before going to the next step of replacing the AMF sensor. Did that, my engine light was reset and all appeared fine for a 3 days until it came on again. Guess I gotta go to the next step.
I see that you're in TO, what price were you quoted for the sensor? I was told it would be between $250-300 Canadian.
thanks and good luck.