Electrical problems

[Chamberpains]

Sounds like your losing power or ground to the ECM or ignition circuit. I'm assuming they cleaned and replaced the fuses, terminals and fuse holders at the battery box. Did anyone go over the connections at the starter? Often times these will work loose, be busted up or corroded. If they all check out, it may be time to get really dirty and pull the wire from the battery box all the way to the front of the truck and ECM down and have a good look at them. There is probably a broken wire somewhere barely making connection.

Another place to check for good connection is in the firewall passthrough connectors. There will be round ones on the driver side firewall and rectangular ones on the passenger side (held in with a 1/4" head screw in the middle) pull those off and make sure all the pins are in good shape and none are recessed or pushed to far in to make a good connection. Also pull on the wires to see if maybe you have a broken one inside the weather packing.