When it was in the shop, when they screwed it up, just about everything was replaced before they would admit they fried the ecu. new wires, plugs, cap, egr, they even replaced an injector they thought was clogged...

It's just so weird, was running great, like a top, then just one day at startup it was all back to square one when the original ecu bought the farm. And I havent touched the engine. Just a radiator flush.

 

See if there are any codes then. Start from there.

 

I'm always skeptical of the "fried" ECU/PCM stories. There are quite a few posts around the Internet where people replace PCMs and it doesn't fix their problems. Don't get me wrong PCMs can fail and with enough malice it is possible to damage one but the people designing these things are not exactly idiots. Pulling sensor supply voltages to ground or open circuit voltages won't damage the PCM but will make it misbehave, all the way to the unit not communicating. The fact that the truck was running fine and then showed the same symptoms with the replaced PCM is an indication there is something else going on. Unfortunately troubleshooting these issues is beyond the capabilities of most "techs".

I looked at the wiring diagrams for the 95 trucks and it looks like there is no difference between federal and CA trucks in terms of O2 sensors. It might just be a difference in calibration which would explain why the CA truck did run with a federal ECU. Probably better