Lucky,

You state reman engine, did the original engine have a cam sensor? If so did the reman come with one? If you had one in the original and not in the reman, will need to install sensor into reman if possible. If not, need to replace reman with correct engine. 4.3's are funny. Depending on the year, multiple things need to be checked when installing a reman. If yes, check to make sure it is connected. If it is, make sure wires were not cut during installation or you may have a failed pin inside the connector. Good Luck.