Regarding My Friends Truck

[Cw72gmc]

He has a 72 gmc as well. We took it through the car wash, we paid for basic. But the lady gave us supreme. It was 15 degrees outise and the truck wasnt quite up to operating temp. The under carriage wash sprayed the engine compartment. About 30 seconds later it died. After numerous attemps to start it.. With the pedal to the floor it would idle 500 rpm with major back firing and irratic firing pattern. Finally got it to idle right but give it any gas it would die.

After 15 mins of idling we drove it home 40 miles. Its running ok but is missing on the passenger side. It will pull out of it and do it again...almost like a weak plug starts firing.

My question is...Where do I start first? Plugs and wires? Did the motor firing like it was foul a plug...Or do you think water made it into the cap and there is just a lot of moisture there?

Please help...