EGR Vacuum Modulator Check
- Remove 3 upper vacuum hoses from EGR modulator. Using fingers, plug modulator paired ports NO's. 2 and 3, and blow air into opposite port. Air should pass freely through filter.
- Start engine and hold speed to 2500 RPM. Using fingers, plug modulator paired ports and blow air into opposite port No. 1. See Figure . There should be a strong resistance to air flow. Replace EGR vacuum modulator if it does not operate as specified.