1996 ford explorer get ? electrical problems? help me please?

i have replaced the fuel pump 3 times. had a ford diag. check and replaced all recomended parts but when ever i reach 55mph it shuts off(leaving me on the side of the road) it can take from 30 min. to 3 days before it will start again. so im thinking electrical. however, ive been told that there are 47 different computer chips for this make. what do i need to do to this thing. the last fuel pump had me running great for about a month then......55mph..and she just shuts off. no one seems to know what the problem is . so i come to the great people of yahoo answers please hook me up:}