Checking EGR System

SYMPTOM
CHECKING EGR SYSTEM

POSSIBLE CAUSES
- Vacuum line to EGR solenoid restriction or leak
- Vacuum nipple at throttle body plugged
- EGR valve assembly defective
- EGR valve assembly does not hold vacuum
- EGR valve assembly tone changed
- EGR valve assembly vacuum <=3 inches
- Passages between EGR valve and intake closed