1988-93 Lemans (Positive BACKPRESSURE EGR Valve)
- Firmly grasp top of EGR valve and check for looseness by trying to rotate valve in both directions. If looseness is felt, EGR valve is defective. Ensure engine is at normal operating temperature.
- With engine idling, push up on underside of EGR diaphragm. If idle speed drops, EGR valve is functioning properly. Observe EGR valve diaphragm and increase engine speed to 2000 RPM. If EGR valve diaphragm moves, EGR system is functioning properly.