engine idling rough, will stall at at stop. also hesitates when accelerating.

What is your question?

could this be a bad EGR valve? I just completed a 300 mile trip, and it started running rough the last 20 miles, after climbing a long grade, 5,000 ft. from Phoenix to Flagstaff,AZ. It's a 1989 Nissan Sentra 1.6L.