2000 Astro, 75000 miles:
The SE light came on a few days before the first incident. Going up a grade on cruise control, the tranny shifts into overdrive to keep the speed up, and the engine hesitates, and then dies. I pull over, check gauges -all normal- and it starts fine, and runs normal. I make it home. Next day I have it scoped, and the engine code reads electrical malfunction. They do a tune-up, all Delco parts: plugs, cap, rotor, wires, pcv valve, and fuel filter. The next morning it tests fine; I gun it on the on ramp and it goes up to 85 no problem (just as a test; I drive 65-70 normally). But later that day it again has the same problem with hesitation, only this time not on cruise control so I back off quick enough to not have it stall out.
Another mechanic checks it (problem with first one honoring his already expensive estimate of $500 or less, with oil change.) Using a SnapOn portable reader, she comes up with either the crankshaft monitor (rpm) or the fuel pump wearing. (I told mechanic #1 it felt like fuel issue) And she tells me not to let the tank go less than half or a third full or the pumps run dry on curves and wear prematurely.
Is the fuel pump the probable culprit? Or is there anything else I should look at? Already ordered a Delphi fuel pump to have in the van ready to go.
Many thanks; this is a great forum.

2000 Astro, 75000 miles:
...she tells me not to let the tank go less than half or a third full or the pumps run dry on curves and wear prematurely.

Complete fallacy. Apparently this technician has not seen the inside of a GM fuel tank in the last ten years. The in-tank fuel unit has a self-contained reservoir which provides almost a half gallon of fuel under all conditions. This helps cool and prevent starvation. GM addressed and solved that problem back in 1998. Anyone who tells you otherwise has not seen a GM truck fuel system recently.

http://www.wwdsltd.com/files/InTankUnitNewB.jpg



Is the fuel pump the probable culprit? Or is there anything else I should look at? Already ordered a Delphi fuel pump to have in the van ready to go.

Only a fuel pressure test will verify that.

When you get the new unit, make sure the electrical connector at the front of the tank gets closely inspected or changed. Also disassemble, clean, solder, and verify the ground connection (in the same location). The factory connection is crimped, and should be thoroughly cleaned and soldered to assure a ground. This is very important, and I cannot emphasize that enough. The ground is often an overlooked item which can create resistance. Even 1 ohm of resistance under full electrical load of the pump can reduce fuel pump voltage from 14.1V (running) to below 10V. Pumps operating at 10V cannot produce the required 61 PSIG to overcome the poppet injector backpressure, therefore stalling the engine.