[petek]

I wonder (and haven't the foggiest idea) if monitoring a single cylinder is a good idea or not. What I'm thinking is that if you monitor say 4 cylinders you'll end up with the sum of the cylinders. If one is a little lean, one a little rich, and the last few are fine, then everything sums together for a good reading. If you monitor a single cylinder and the cylinder tends to run a little lean, the ECU would (in effect) make all of the other cylinders a little rich.

Of course what would be really cool (and massive overkill) would be to monitor each cylinder and adjust the timing on individual injectors to keep each cylinder perfectly in tune!