How to clean a EGR Valve? Also randomly stalls and rough idle until warm.

When I start my car it barely can even start. It gives a real rough chug like its not getting fuel then it shuts off. I restart it and it will get going. Though after I park and go into a store I come out and it chugs once again till I give it full throttle and it gets to a normal idle. I have tried to remove the egr valve to clean it but can't remove it. Any help? Also I replaced the spark plugs last year. I put a new fuel filter in, the old one was very dirty. But it still feels like its just not getting the power or gas it should. One other thing I ran it about 6-8 months with a couple good sized holes. I had it fixed last week. Could that do with how horrible its running! Please help!