Good talking to you today Mike. Thanks for calling and getting my theory complete. I'm going to revisit Banish's book to see if there was just something I missed in the reading. Pretty cool how the deceleration caused by the misfiring cylinder is measured and seen via the crank trigger an wheel and is then back up verified by the O2 sensor to provide that CEL should it occur. Pretty cool as well how you can actually shut off the one O2 sensor and then set the other up to monitor 8 cylinders on the turbo setup above. I would have not thought the PCM (stock one anyway) would have been that versatile. I get into this kind of stuff. It's similar to what I deal with daily at work. For me to do what you do I have to upload the ladder logic from the PLC, make corrections of modifications to it and then download it via a laptop with the associated software. Thanks for taking the time to call and walk through it with me and get me straightened out.