COULD HOSING DOWN ENGINE WITH GARDEN HOSE CAUSE.

It shouldn't but it is possible. You have to be more specific on what the symptoms are or why you suspect the coil has failed. Keep in mind that water from a hose is no different than driving in the rain, however, I did take out three ignition modules on older GM front-wheel-drive cars in the early '90s after pressure-washing the engines. To be safe, blow the water off then let it air-dry before trying to start the engine.

The larger amount of water can overload the insulation on some electrical parts if that insulation is already old and deteriorated. Fords are no strangers to electrical problems and water doesn't make that any better.