Isx shutting down randomly

I have a isx it’s been in the shop 2 weeks. The truck is randomly shutting off. It seems to need to prime to get started again. Last night and $3200 latter they called and said it was done. I drove the truck off the lot and it shut down 3 times in 2 miles so it’s not fixed. They told me the ecm is randomly loseing contact with the engine they changed the lift pump and two power wires. They are saying the ecm is bad but my trusted mechanic said no way he just tested the ECMs few weeks ago it’s fine don’t let them change it. I wish I was at my trusted mechanic and not the road. He did put a new engine in my truck about two months ago. sometimes the new lift pump won’t kick on to prime then the truck won’t start at all. Other times when the truck shuts down the lift pump cycles the the truck will start after the priming cycle. After starting the fuel pedal seems to be unresponsive for alittle bit. Does anyone know any known wires to check or any info for me to try. I’m not exited about calling the dealer that just got done working on it to try again. I did post this question a week or so but I have more info now so I started a new thread I hope that was ok. I was pretty vague in the last post I did not know as much abou the problem then. Engine is a 03 isx CM570 600hp in a Freightliner classic.

 

I’m sitting here staring at the engine in discust will try it thanks.

 

I assume so but not really sure

 

Sitting here turning the key on it seems like after about a minute of having the key on the ecm will click then the lift pump starts to cycle. Like it take a minute to start.

 

The truck sat all night now it’s acting up right away so the ecm and engine is not hot yet