miss firing

Sounds like the engine needs some maintenance, a tune up, moisture had gotten on some electrical parts that are starting to break down.

right, you got water in the engine electronics, somewhere- I hate those car wash thingies- if you are lucky, it might just dry out-

Duane, Check your O2 sensor harnesses to make sure there is no water present. Are you getting a check engine light of any sort?

I bet you got moisture around the spark plugs and coils. Triton engines are very sensitive to moisture on the engine. I would pull the coils and dry things out and put dielectric grease on the coil boots when re-installing them,

Check the code to make sure it is water related. Most likely to be a misfire. Follow full_of_regrets advise