A gas port that is too small will definitely cause it to act exactly like your rifle does. Before you start drilling it (which may be what it needs), there are other questions about the rifle to be answered.
1. How many rounds do you have through your rifle? What ammo are you using?
2. What length gas system? Carbine, mid length or rifle?
3. What length is your receiver extension (buffer tube)? Rifle or carbine? What is the internal depth of it?
4. What buffer length are you using and how much does it weigh?
There may be more but that's a good start.