Valenz480

Hello guys! New member here. My name is Gilbert and I reside in Arizona 🌋. Well just bought my first 97 Mustang gt 3 weeks ago. The car was running fine up until Saturday. Dun dun duun.... Started hesitating badly while on acceleration. So I changed fuel filter and no help. Checked spark plugs and then noticed coolant in cylinder number 5!!!! Car did blow a heater hose but that was replaced. Burped the system installed a new temp gauge and no overheating/ no smoke what's so ever ran fine. Now I found out that I only have coolant in cylinder 5. I went ahead and dried it out installed new spark plugs and spark plug wires and ran better. Not 100 % like it was, but a little better. So question is could it be the IM gasket? By the way it has the aluminum coolant passage. Much help would be appreciated! Don't want to drive it like this at the moment. Thanks!