Hello; I had the same problem, and it was the Solenoid. You will have to take-off the grip frame; then you will see on the top 2 HEX screws , that you have to loosen order to take the Solenoid OUT(they might be pretty tight).
Than you have to take out from the back of the Solenoid the Pin valve, inside you will find 2 small Orings that you have to replace and thatīs all.
The Orings Iīve found them in a Shockers repair kit that I have; but also if you donīt have one and you need a quick repair of your gun , Iīve found that you get it from a lighter .
I hope I could help you.
PS: sorry about my English writing but I live in Argentina.