i have a 91 f150 supercab 4x4 w/351w it will run for a few min and dye.Before it dyes the trans will shift hard and it will start right back but it wont take off in drive only in lowif you shift it to drive it boggs down and quits.you can let it sit for a while and everything will be fine.it doesnt do this all the time.any help is greatly appreciated.