[JMJNet]

Glad you get it fixed. PMD can be an issue anytime regardless of whether you like it to happen or not. By moving it outside the hood, hopefully, it help prolong the life. I am not sure what is the situation in bus, I suspect you should have a little more space.

The resistor should not cause a stall unless you happened to be in the time when ECM is asking for a resistor value which should happened once in a blue moon kind of a thing.

 

[JMJNet]

I will check the LP first, although you assume it is working but have you checked it?
Bad LP can cause air.

How is the fuel filter?

 

[JMJNet]

The IP harness where the PMD hooked up into can be bad.

I am assuming those PMD are mounted on a good heatsink if they are not on the original IP location?

Where did you get them from? May be the extension cable is bad?

Did you ever check the LP as suggested above?

 

[JMJNet]

Get a wire brush and clean them good. No need to replace the ground wires.

The positive cable, on the other hand, may be worth replacing if they look bad.