EGR valve sticking is a common problem from what I have read on other boards. I guess the carbon build up cloggs the valve and prevents it from moving properly. Had this happen on my 01 Rodeo Sport. I took off the egr valve and spayed the inside with some carburator cleaner to wash out some of that build up (dealer recommended on som other post). Didnt see anything come out, but the checkengine light dissappeared (had the High voltage egr code) and no more stalling on red lights.

P.S. If you do this, make sure to wait a while after driving, the egr valve stays hot for a long time.