95 contour code 332, 543

95 contour V6 (OBD-I) running normal, intermittent check engine light and overdue for emissions.

Cleared old codes, ran for about an hour, KOEO test no current codes but stored codes set in memory, 332,543. Started checking egr, sucking on hose connected to EGR causes engine stumble at idle. Feeling hose that I took off EGR I feel pulsing vacuum.
Any suggestions on where to look next?

543 - Usually ignore, it's due to a stall.

332 = P0401, one of the FAQs around here. Since you do have EGR flow (can't verify if it's the correct amount, though), I'd suggest doing the DPFE diagnostics .

BTW, you should NOT have any flow to the vacuum line at the EGR valve while sitting in the driveway at idle. You might have a second fault in the EGR system.

Steve

OK, thanks. I'll look further, might be wiring related the harness is really bad on this car and the control to the EGR solenoid has copper showing (but not touching as best I can tell).