Engine shut down and gages/ fuel pump shut off.." no bus " on the odometer

Sound,s like the ECM may be going bad if random cut off.

Ok I'll give that a try .. thank you

Would taking the engine and computer out of a 99 an putting it in a 2000 create the"no bus" problem etc....

yes possible,

What numbers should I be checking for a match

The ecm numbers

If different from the original that was in truck,different year model different sensor,s and wiring harness,will run but may have other issues.

On that thought...with the 99 engine in the 2000 truck/ ECM..I lost overdrive ...but by putting the 99 ECM Into the 2000 truck I got overdrive back ...but now the no bus an shutting off issues... almost have to be a difference in ECMs

Bingo! you got it.. PCM and instrument eeprom don't like each other and aren't communicating not to mention the PCM is different from '99 to 2000

I can putt the 2000 ECM back in and see what happens...but what about the loss of overdrive... surely the transmissions are compatible?

Ok did the ECM switch back ..now I'm back to only having a 99 engine and transmission in a 2000 truck...the no bus indicator is gone and truck runs great....but I lost overdrive?????

Mine does the same thing cuts off but starts right back up after it cools down for a minute mine's a 2000 Dodge Ram 1500 put a new fuel pump in it and it wasn't it

Didn't see this till now, the ground wire going from the front of the drivers side head to the ecm needs checked or replaced with the next larger gauge wire.