antifreeze in the ignition cylinder

I believe that it is the ignition coil and not the ignition cylinder that you are replacing. I am assuming the motor is a V-8 and not the 4.2L V-6. There are no service bulletins for this vehicle in relation to the coolant leaking into the spark plug tube. Did you inspect the coil again after the latest scan? There is no water jacket close to the spark plug tube for cylinder number 5, so I am curious to how the anti-freeze got into the area of the ignition coil in the first place. If you have inspected the coil and no anti-freeze was present then you may have a bad spark plug or spark plug boot. When coils are replaced and the old spark plug or spark plug boot are reused, you could have the same problem, a cylinder 5 misfire. Were the fault codes cleared after the first repair? If not the cylinder #5 fault may have been retained in the engine control module memory. You need to verify that you do not have the reappearance of coolant where the coil sits and if coolant is not present, you need to see if the spark plug or previously mentioned boot are ok. If coolant is present, you will need to pressure test the cooling system and find where the coolant is coming from. When you said the anti-freeze was in the ignition cylinder you meant in the cylinder it self, (anti-freeze on the spark plug electrode) then you will have to check for a leaking head gasket. Good luck.

My 1998 F150 gave me a #5 cylinder ignition error. Pulled the plug and the spak plug tube was filled with antifreeze. If you are getting AF in the spark plug tube, it's not likely the coil, but the AF is causing an ignition fault. I am trying to find out the source as well.