Well, then back to a probable electrical problem somewhere... something's not making good contact causing these codes (and "ghost" codes) to get triggered. Start unbolting the ground cables from the front of the engine and use a dremel tool with rotary wire brush to clean the terminals and the surface of the block where the terminals are bolted to it (use a dab of marine grease under the terminals before you bolt them back to the engine). Check the battery cables for any signs of corrosion inside the cables (brittle stiffness in the cables or white powder coming out the ends). Look for any places where wires could be rubbing against metal. This just isn't going to be fun to figure out unfortunately.
- Michael