Accord 1987-89
1. Check the vacuum line for incorrect 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. Vacuum should develop within 10 seconds.
4. If there is no vacuum, proceed to check #1 of the idle control solenoid valve. If vacuum is formed, increase the engine speed to more than 1500 rpm and check for vacuum. There should be no vacuum.
5. If there is vacuum, proceed to test IAC solenoid valve #2.