Sputtering engine on 92' Ford F-350 will start but not run properly?

I have a 92' Ford F-350. The truck ran fine until I washed the engine (gently) with a hose. It may not have anything to do with the problem but the truck will start and run very rough. The engine sputters as though there is a fuel loss and a slight knocking noise. if you apply fuel it will pick up RPM's, but still the same rough run. The distributor cap, wires and rotor have been changed. Ignition module has to be in the cab as it is not mounted or found on or near the distributor. The plugs are new (4-months) but I will change them again. no trouble lights, no diagnosis from a trouble meter. I will OHM out the coil pack anything else I can do to make my beast run?