MY 89 f150 4.9L straight 6 has been kind of sputtering at around 50 mph but stopped when I gave it gas. Today it stalled while driving like the gas just shut off. I tried to kick it over but nothing until I mashed the gas a few times and it started and ran for about two miles when it shut down again and now won't start at all. I am going to change the filter but what else could it be? I just filled up and changed the oil about a half hour prior to all of this. Gotta get this handled tonight. It is my daily runner. Thanks