Coolant in Cylinder 5. Whats the cause?

ford has huge issues with the corners of the intakes leaking and filling the cavity of the coil boot with coolant and causing missfires and such. when you remove the plug, the coolant goes into the cylinder. I would get a pressure test to confirm the intake is leaking. if it is not, then you may have a blown head gasket. let a shop confirm it for you. Roy