Hello.... The EGR valve, or Exhaust Gas Recirculation valve, is a vacuum controlled valve which allows a specific amount of your exhaust back into the intake manifold. This exhaust mixes with the intake air and actually cools the combustion process. Cooler is always better inside your engine.
To check if you have a bad EGR ,just apply vacuum to the valve with engine run.
If the engine stalls or start running really bad ,your egr valve is good .
Other wise ,you need to check the egr solenoid ( it should click when ground one of the 2 wires) and the vacuum hose going to it, make sure they are not broken.
Yes , you need to remove the egr valve and see if anything keeping it open(piece of carbon).
Also vacuum leak on the valve itself (bad diaphragm) will make it run rough.
Good luck.Accept my answer if i helped.