PSD The OBD II connection under the dash is powered off the under hood fuse #14. The ground on the connection under the dash is #4.
You can find all this info in the service manual in section 8E. Sorta looks like a ground problem. Did you take the connections apart I mentioned in the 3 post and clean them all well?? The ground for the Powertrain Control Module (PCM) is just forward of the fill for windshield wiper fluid. It is a nut that if I remember it has four brownish wires connected to it. There is a small black box next to it that has major fuses it it. You may what to open that box and check them also.
Have you checked the 6 fuses on top of the RCM?? especially the #3 and large orange one??