Diagnostic Aids

WARNING: This page is about a different car, the 2003 GMC Sierra, 2003 GMC Cab & Chassis Sierra, 2003 Chevrolet Silverado, and 2003 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

Inspect for the following conditions:

Vacuum leaks and restrictions in the EGR control system vacuum lines.
Vacuum leaks and restrictions in the EGR control system components.
A stuck closed EGR vacuum vent solenoid.
A stuck closed EGR valve vacuum control solenoid.
Proper vacuum line connections.