That is the round thing on the top rear of the TBI. The thing that looks like a carburetor.
In the throttle body.
Under the upper intake manifold, attached to the bank of injector poppets, aka "the spider".
oil pressure switch or knock sensor
The recommended spark plug gap on a 1996 Chevy C1500 with a V8-305 engine is .060"
On a 1994 Chevy C1500 5.0 V8 it is the top valve with a black cover next to the coolant resivoir
its part of the fuel rail and has vaccume line connected to it
It is inside the upper intake manifold. To get to it you must remove the throttle body, upper intake manifold, and several electrical lines and fuel lines.
350 tbi
0.035
It is located behind the distributor.
Have a fuel pressure test run.
Right behind the distributor and it is tough to get to.