Another update. I just removed the two brand new Bosch F8DC4 plugs that I installed in cylinders 3 & 4. I installed those yesterday just for the hell of it to see if this problem was the plug. Both new plugs I removed today were completely clean, the tips/electrodes were as clean as they were when they came out of the box. Which means that neither cyls. 3 or 4 are firing. Obviously cylinder 3 gets its command to fire from the coil, #4. I just now reinstalled the same older Bosch F8DC4 plugs back into their cylinders. I also swapped out the OVP with a used known functioning one - no change, still the only code I get is #23...

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