There is no inertia switch on the Chevy truck it runs from the ecm , oil pressure switch and relay.
It controls / regulates the fuel pressure.
The 1974 Chevy truck has a mechanical fuel pump with a built in pressure regulator.
21
The fuel pump is kaput.
The mechanical fuel pump regulates the fuel pressure. This truck is not fuel injected. It has a carburetor.
use a pressure guage hooked to the scrader port on the fuel line.
It is in the throttle body.
From 87 to 95 did not have them. You will have to crack the fuel line alittle to relieve fuel pressure.
It does not have one, It is controlled by the computer and sensors.
41 to 47 psi.
Check the fuel pressure but it's most likely the fuel pump.