Vacuum Advance

Install tachometer and timing light. Ensure engine coolant temperature is at least 140°F (60°C). With engine at correct idle speed, note amount of advance. Advance should be within specification. See TIMING ADVANCE SPECIFICATIONS table.
Disconnect vacuum line from pick-up. Accelerate to 2000 RPM and note advance reading. Advance should be within specification. See TIMING ADVANCE SPECIFICATIONS table.
Install vacuum pump on vacuum hose. Apply 8 in. Hg vacuum. Accelerate engine to 2400 RPM and note advance reading. Advance should be within specification.
If advance is not within specification, replace vacuum sensor. Repeat advance test procedure. If readings are still not within specification, replace ignition ECU.

TIMING ADVANCE SPECIFICATIONS