D 250 Pickup V8-360 5.9L VIN W (1987)
Cruise Control Vacuum Reservoir: Testing and Inspection
1. Disconnect vacuum hose from servo on all except 1986-87 Mini-Vans/Wagons, or from vacuum reservoir on 1986-87 Mini-Vans/Wagons, then
install a suitable vacuum gauge into hose.
2. Start engine and run at idle. Vacuum gauge should read 10 inches of Hg.
3. If vacuum gauge reads below 10 inches of Hg, check for vacuum leaks or poor engine performance.
