C 20 3/4 Ton Pickup 2WD V8-350 5.7L VIN L 4-bbl (1983)
Manifold Pressure/Vacuum Sensor: Description and Operation
Computer Command Control (C-3) System
The vacuum sensor, mounted in the engine compartment, measures changes in manifold pressure and sends this information to the ECM. The changes in
pressure indicate the need for adjustment of air/fuel mixture and spark timing (EST) to maintain good vehicle performance under varying driving
conditions.
