Why would a 91 Nissan Sentra 4-cylinder STD stall occasionally when coming to a stop?
Answer Its your EGR valve.
Had the same thing constantly happen on my '93. Its your EGR
valve that's sticking. Nissan uses a plunger type valve that's when
sticks stalls the car. Find the valve (looks kind of like a
spinning top) and while your car is running reach under and using
your fingers move the plunger. This will stall your car. Replace
the valve and drive happily ever after. This fix is definitely a
DIY as it only takes a wrench and or ratchet.