B4000 Regular Cab 4WD V6-4.0L OHV (1997)
EGR Valve: Testing and Inspection
Inspection
1. Install a tachometer.
2. Disconnect the idle air control solenoid connector.
3. Remove and plug the vacuum supply hose from the EGR valve.
4. Start the engine and run it at idle with the transmission in neutral.
5. Observe the idle speed.
6. Connect a vacuum pump to the EGR valve and slowly apply vacuum.
Specification: 17-34 kPa (5-10 in.Hg)
7. Verity that the idle speed drops more than 100 rpm with vacuum applied and returns to normal after the vacuum is removed.
8. If not as specified, replace the EGR valve.
