trace - when the truck gets the "no bus" combined with shutting off, it might be the crank position sensor. i don't know why, but a lot of people seem to have problems with aftermarket crank sensors. so - if you can afford it, just get one from the dealer, or an oem one from the junkyard.
there's some very good, very old threads about no bus from ... i can't remember... a dodge tech from a long time ago.
he said - when it was showing a no bus - to unplug all the sensors and see if it would go away. then plug them back in one at a time and see which one triggered the problem.
RABBLER - http://dodgeforum.com/forum/2nd-gen-...-bus-mean.html