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!