I recently picked up a beautiful 78 Stang. It has the 2.3L engine and it ran well - that is up til yesterday. I changed the spark plugs and wires, and put on a new valve cover gasket. I started it up and it ran well. Then about an hour later I took it out for a drive. When shifting it into second it simply died, not to start again. It turns over but I'm not getting any gas to the cylinders. A couple have suggested that my timing belt must have slipped. Anyone have this problem? What do you suggest?