Say you don't have an apparatus that applies vacuum what you can do is take the egr off and push down the valve with a thin screwdriver. Then find a way to maintain vacuum. I used an old tweezer cover over the vacuum nozzle and it did a good job. Reattach the egr and start the car and let idle. If it runs like a helicopter your egr passageway is clean. If no change that means egr blockage.