ever since i drove thru a small amount of water on the road my mustang runs rough.ive had it at ford they have changed a 02 sensor three coil packs and when the car gets above 4grand it breaks up sometimes just driving down the road you can notice a small miss it doesnt do it all the time .HELP

 

I'd say you need to get back to the dealer / go to a different dealer.

 

how much is a "small amount of water?" does your car have the factory air intake, or an aftermarket setup?