Ford: car dies when under load-rough idling, double pumper, accellerator

Question
1976 ford pick up with mustang 302 holly double pumper four barrell carb.
truck was running fine, son took it to car wash, rinsed off the engine, came back..parked it.  went to leave, was hard starting and didnt want to stay running as though it SUDDENLY had a missing spring or something on the carb. dunno if it's SUPPOSED to but the butterfly on the carb does not actuate when the accellerator is pressed.  noticed that one plug wire had laid on the intake and burned, not COMPLETELY thru, but enough to think this MAY be a part of the problem, if not...certainly WILL be in a short while.  thought it might be a vaccum hose but there are only TWO and they seem to be fine. what else might we check before going to a garage?
THANKS for your help.
doug

Answer
Doug,

Your damaged plug wire is definitely contributing to your over all problem especially if it was like that before your son rinsed off the engine. Secondly, yes the butterfly on your carb is supposed to actuate when you step on the accelerator. I would also suggest pulling your distributor cap to check and see how much water got under there. You need to change the plug wires, too. On the back of the intake manifold, there should be more vaccum lines that you could check. Hope that this helps you and if you need further asistance, please do not hesitate to contact me. Good luck.

Ken