Vacuum Control Valve Check

Disconnect the vacuum hose (white stripe) from the vacuum control valve and connect the hand vacuum pump to the vacuum control valve.
Plug the end of the removed vacuum hose.

Fig 1: Plugging Vacuum Hose
Courtesy of MITSUBISHI MOTOR SALES OF AMERICA.
Start the engine and run at idle.
As described in the chart below, check the vacuum condition.

ENGINE VACUUM CONDITION CHART

ENGINE CONDITION	NORMAL VACUUM CONDITION
Idling	Approximately 21.3 - 24.0 kPa (6.3 - 7.1 in Hg)