Passing along this in case anyone else is trying to diagnose a possible cause of these error codes. My Gen 1 S10 would trip these error codes intermittently. Causing the engine to run on one cylinder. It would run fine for several hundred miles then misfire. After consulting the factory service manual and doing the diagnosis procedure I could not find the issue. After months of trial and error I found the cause. Every one of the modular waterproof connectors from the wiring harness to the coil packs / Plug caps had lost their spring tension on the spade connectors. The modular connector snapped on positively and each one tested ok for continuity. Only open pulling the actual spade connector out of the waterproof connector and trying it directly on the male spade to the coil/Plug cap did I discover it had a loose fit with no tension to grip the male spade. Vibration would cause a poor connection and fault code in the bikes icu. The fix was to purchase a used wiring harness with good connectors and splice then onto my bikes harness. Hopefully this might help anyone out there who's got one of those error codes above and is having trouble diagnosing the cause.