Yes, it was not until the last breakdown that I realized the pattern:
The first stall incident happened with my wife on 5/10/12 This happened while she was driving on pavement but had just gone over some railroad tracks.

The second breakdown occured when I was coming home from work on 5/31/12. I had just gotten onto the bumpy dirt road I live on when it stalled (I was able to coast it downhill all the way home on this occasion )

Kind of points toward a wire intermittently shorted to ground, right?

 

I finally got around to performing more troubleshooting last night. I was delayed by the unfortunate fact that I left the key engaged after doing some troubleshooting one night. 3 days later I noticed that my battery was totally toasted. I attempted charging... left on charge for 2 days. Voltage remained less than 4 volts (really drained!). I finally got around to replacing the battery last night. I noticed before replacing the battery that the supposed fuel pump shorted to ground no longer existed (checked resistance from right side of the fuel pump fuse socket to ground - read around 5 ohms). After the battery install, I turned the key to the ON postion and the pressure immediately came up to 59 psi and steady (see picture attached). I started it up and it ran fine for 30 minutes while I searched for grounded wires. I was initially planning on dropping the tank to find the shorted wire, but without having a ground currently in it seems a bit hard to pinpoint. I was able to get a decent look at the wire routing from the tank all the way to the front of the vehicle. Nothing seemed out of place or like it was being pinched by anything. The wire for the fuel pump runs inside a plastic wire sheath along with a bunch of other wires. So unless some of the wires are shorting to each other within the plastic sheath, or it is shorted to ground above tank, or where the wires are not easily accessible up front, I can't figure where else it would be shorted out.

I have come up with 3 outside the box ideas that may have changed the state of the wiring fault since I last noticed that the fuel pump circuit was grounded:
Temperature
Barometric Pressure
Gremlins

Since I can not control any of the above conditions, I am at my wits end.

At this point I am thinking about just driving it back and forth to work everyday until it happens again and then just get it towed to a GM dealer (now that I have a 3rd vehicle, I could leave the vehicle there until they figure it out).

Note: As stated in previous posts, I don't know that I have fully ruled out that this has to be an issue with the wiring that runs under the truck to the pump (due to the fact that I am not fully confident I have read the electrical prints correctly). I need an H3 wiring expert to help me there
Any other suggestions about what to check on this? Unless there are checks that can be done without the circuit faulted or something that I can do immediately after stalling while on the road, I will probably just be towing it to the dealer next time. I have already replaced the high dollar item (fuel pump). So how much more could they really bill me for?

 

How much? Diagnostic time to find the problem at whatever their hourly rate might be, and they will not rule out the fuel pump just because you replaced it.

 

You must absolutly verify the voltage on the control relay,coil and contacts at the moment the pump stops. I think some other system is killing it.
You could hook up a light or led to monitor those points. If a fuse is not blowing the voltage is being cut off by something?
No codes?

You should also post a copy of the page,119, so we can see what you see.

 

Hi,

I live not too far from Delta. I use the gym there.
I am in Pequea.

Patrick