My 97 catera is mis-firing, I have removed and ohm'd the coil (it is with in specs,both the primary and the secondary) I have ohm'd the plug wires, all 13k or below. I tried a different coil today, no help. The cylinder banks 2,5 fire fine, banks 3,6 fire fine, bank 1,4 are not. The tower #4 is okay but tower #1 is producing no spark. It does the same thing with a known good coil. I ohm'd the wires between the coil connector and the ecm, they are good. Could the crank sensor or the camshaft sensor cause a problem? voltage at the B+ coil connector is 13.41 running. I even tried to run 1&4 from the #4 tower but it still feels as if it is running on 5 cyl. No power and shakes when idling. I took a reading with my fluke in rpm mode, cyl one is erratic as heck. When you rev the engine the reading drops off to 0.