Ok I got an 07 Monte Carlo that cranks but no start I had a new fuel pump installed as well as checked all fuses and connections cleaned battery terminals and have spark but I have no fuel pressure and I am able to drive it sometimes a week to a month or not even a days worth of driving as well I'm not sure what else to do Im just confused maybe I don't know much about this issue except what is explained

 

How did you prove during a no start that you had spark?
How do you know you don't have fuel pressure?
Does the security light stay on when you leave the key in the on position?

 

I pulled a plug and cranked it and there was spark and the reason I know there was no pressure was when I pressed the valve relief nothing came out and the light does not stay on I just got the car I'm not much of a Mechanic and from what I know it just had a new fuel pump installed she got tired of it not wanting to start whenever it fealt like not running so it was Givin to me and I'm determined to get it running the way it should now I was doing some research on the vats system cuz I don't hear the fuel pump ever kick on even when it does start so wut I'm getting at is she had a key made for it because she locked her original key in the car so the locksmith came out and made her a new key but the original key from when she bought the car from someone didn't unlock the door but only worked in ignition and that's the same way her new key iz so I read that if it's just a learned key and not the original master key the vats system will sometimes kick on and not allow the fuel pump to send the fuel as a theft deterent so I'm wanting to know if they will b able to get another copy of a master key that works in both door and ignition will it solve the problem cuz I guess they had alot of problems with this issue I am trying to get a better understanding of things as I said I'm not much of a mechanic myself and the car iz in great shape with only 130000 miles any suggestions would b great