My 86 f-150 300I6 acts like it is running out of gas to where it will sputter and it will die for a few seconds and then it will fire back up again and it will keep on doing this till u stop. It will only do it after you drive down the road for about 10 miles. I know its not out of gas because i had just filled up. and once the truck cools down it will run fine. i was thinking it was the fuel pump and/or the fuel filter. any help would be great