Blown Head Gasket HELP
My 97 Mustang V6 3.8L recently Blew a head gasket. 152,325 Miles. I'm not very experienced in engine work but I'm replacing the head gasket myself. I don't have 2K to get it done at a shop. I have been told that before I take off the heads, I have to make sure the engine is in DTC or else when I take off the heads and replace everything, I'm going to mess up the factory Tune on the Stang. Is that true? Any and all help is much appreciated!!