PO341 code

I got the front end of my truck in a hole and the fan was slinging water on the engine. Now heres the problem the engine started running rough and backfiring out the exhaust and it runs rich. Put a scanner on it and the only code it throws is the po341. I've had it in 2 local shops and both have told me that it is electrical cause all the checks on the engine was good such as timing, compression, fuel pressure and all that stuff. I've changed out the entire distribitor including camshaft sensor, crankshaft sensor, map sensor, MAF sensor, the computer, battery, the fuel filter, the coil, ign control mod, all plugs and wires and the fuel injectors. The thing I'm on now is the alternator cause when I checked the voltage while idleling it was surging from 12 to 14 rapidly so I took it off and autozone check and said it was good. I'm out of ideas on what to do next. I've also check grounds and chased wires and checked with a mutimeter. Ive got a lot of time and money in this truck and dont want to put it in another shop just to pay them for nothing. Thanks for any ideas and help.