FS Tippmann 98 Custom

believe me i oiled the gun and it does not work, i even went to the extent of puting the stock sear spring back in and buying an o ring kit and replacing all of the o rings, the gun still does not shoot. It is not locked up it just constantly lets air out. you pull the trigger and it just flaps like it would if you were running out of c02. Even adjusted the velocity and still doesnt work??? answer that.