2000 Silverado would not start. Turned over fine, check fuses, heard pump turn on. I will give you my exact findings then explain the hell I went through to get to them.

Measured pressure at fuel pump=70 psi
Measured pressure after filter=70 psi
Measured pressure at schrader=0 psi
Disconnected fuel lines at top of engine and measured psi=2 pounds
Disconnected fuel lines at tank and blew air through to disconnected fuel lines at top of engine=80 psi
Answer= weak fuel pump replaced pump fired up beautifully.


The hell I went through: The internet told me it was my passlock. rewired ignition= no dice. You see even though the 2000 silverado has flashing security light, there was no resistor on my key so the truck wont be locked out by the passlock. The internet told me it was my mass airflow sensor. Pulled connector and actually had to replace a wire now due to this misdiagnosis.

Moral of the story. Hook up a code reader to see if you have codes. If it is something electrical you WILL get a code. If its a mechanical failure you will not get a code. In my case the fuel was not getting delivered so I took parts out of the loop to make a diagnosis.

 

Harbor freight is your friend for weekend warrior mechanics like myself. I picked up all fuel testing and fuel line removal tools for 40 bucks

 

I also have a 2000 Silverado 4.3 l I had the same exact problem mine broke down three times in one week on the same stretch of highway The first time I replaced the fuel pump and the throttle position sensor . it ran for a week and died again. I replaced those parts again along with the fuel pump relay and fuel filter because I figured one of them went bad. it ran two more days and died then I replaced the coil it ran for another day and died. With my truck still along the highway I changed the fuel regulator the ignition control module the distributor cap and rotor and the crank sensor all with no luck. every test I did with the multimeter and the test light showed that I had power and ground everywhere I almost lost my truck to the county because it was too far from home to tow. luckily someone lent me the money. it took me three more weeks to figure out that the wires going to the coil from the harness we're stretching and broke apart inside the casing of the wire. they were touching enough that it showed 12 volts but wasn't enough to fire the coil. I bought a connector for $33 and it started right up I wasted a lot of money that I shouldn't have for something as simple as a broken wire

 

Do you have any OBD II codes?