Accord 1987-89
1. Check the vacuum line for erroneous connections, kinks, blockages or accidental disconnections.
2. Disconnect the lower vacuum hose from the idle air control solenoid valve to the air chamber, connect a pressure gauge to the hose.
3. Start the engine and check for vacuum. A vacuum should form within 10 seconds.
4. If there is no vacuum, proceed to test No. 1 of the idle air control solenoid valve. If a vacuum develops, increase the engine speed to more than 1500 rpm and check for vacuum. There shouldn't be a vacuum.
5. If there is a vacuum, proceed to test #2 of the idle air control solenoid valve.