Note On Intermittents
With engine at idle, manipulate EGR solenoid connector and related wiring. Listen a change in idle quality.
Drive vehicle with throttle angle at 8-15 degrees and engine at 1450-1650 RPM to try and duplicate code. Remove EGR valve and check excessive carbon build-up that would restrict EGR flow, or foreign materials holding EGR valve open. Check pinched, cut, kinked, misrouted or blocked vacuum passages and/or vacuum hoses, reducing EGR flow. Check EGR valve binding in up or down position.