I've got a 94 T-bird. Have a CarMD scanner that seems to work on it, but it hasn't shown any codes on it. It says to just plug it into the port with the ignition in the run position. Didn't mention anything about having the engine run. Was wondering if there's a newer scanner available for our Birds that would let you know what's going on with the engine running. I use Mac computers so the scanner needs to work with that or be a web-based one. Don't want to spend a whole bunch. The car has 65,000 miles on it and am wondering if the O2 sensors need to be replaced. Would a scanner say if they need replaced? Do our Birds have 3 or 4 O2 sensors?