A very expensive spring pistol

Hello I have a WE tech green gas Glock 17 it won’t shoot normally, basically it’s not cycling back it’s acting like a cheap springer and a bad one. I have to physically close the slide every shot. Anyway I have tried cleaning it, tried changing the o ring on the nozzle (I’m pretty sure that’s the problem cuz it won’t pull it). Next I was gonna try to buy red gas so the psi is higher. Help if you have any ideas.