Powers down randomly 2005 E450 6L
So I have a pretty strange vehicle, apologies if this isn't the place.
Bought a decommissioned E450 ambulance 6L and already did a good amount of work on it. Replaced the fuel injectors, the alternator belt, and the solenoid in the transmission. We were still running into some transmission issues so took it to the shop. After working on it they say they can't find any other issues, but its still doing this thing where about a fifth of the time I switch to reverse or stop at a stoplight the whole car powers down, the "Check Gauges" light turns on in green and the smaller "Check Gage" light turns on in red.
Batteries just replaced, oil just checked.
It always turns right back on fine, but obviously this isn't ideal. I'll bring it back to the shop if I have to but first wanted to see if any of you guys had an idea what might be going on.
Appreciate any help at all, thanks everybody.








