Initial Inspection and Diagnostic Overview

This check is to be performed with the engine coolant temperature at 176 - 205°F (80 - 95°C).

Purge Control Vacuum Inspection:

1. Disconnect the vacuum hose from the Throttle Body purge hose fitting and connect a hand vacuum pump to the fitting.

Purge Port Vacuum Curve:

2. Start the engine and check to see that, after increasing the engine speed, purge vacuum is kept constant regardless of the increased engine RPM.

NOTE: If the vacuum does not respond as specified in the test, it is probable that the throttle body requires cleaning.