I have a friend who has a 01 Mustang GT. He cleans his engine bay all the time. When he cleaned it for the first time, his coil on plugs got water seeping into them. So they got fried, 2 of the 8.
So now he cleans the bay and drives the car right after to let the water dry with engine heat before water can sit and seep into things.

I would advise driving right after the cleaning to dry off excess water. Also dont get water into alternator.