Note On Intermittents
With engine at idle, manipulate EGR solenoid connector and PCM connector and related wiring. EGR solenoid should remain energized (circuit No. 435 grounded) to block vacuum to EGR valve/vent vacuum to atmosphere. Listen for change in idle quality. Drive vehicle with TP sensor at 8-15 degrees and engine speed at 1450-1650 RPM and try to duplicate code. With engine at idle, apply and release vacuum to EGR valve to check if EGR valve is binding. Turn engine off. Remove EGR valve and check for excessive carbon build-up restricting EGR flow or holding EGR valve open. Check for plugged or leaky vacuum hoses.