Are you not sure which kit you have? I would like to know to help you out a little easier.
I have an idea to possibly help.
First, disconnect the nitrous line from the throttle body. Then bypass the fuel pressure safety switch by just connecting the 2 wires together. Then have someone sit in the driver's seat with the key on (car off) and the toggle switch ON. Then hold the nitrous line (with a rag, cause it will be cold) pointing away from you and the car, and tell your helper to floor it. This should activate the system and spray nitrous through the line. This will let you know if the line is clogged or not. If you are unsure, then just remove the bottle from your trunk and then briefly open the valve to compare the flow of nitrous. It will be a slightly different amount because of the orifice size, but you will be able to tell if enough is coming into the engine.
Bottle pressure will normally go down as the bottle starts to get empty. But also, temperature has ALOT to do with the pressure. If the bottle is cold, then the pressure will go down, and therefore it wont spray as hard and hp will decrease.
I was actually talking to a shop owner today about this and he said he's actually seen bottle pressure get upwards to 1500psi with only 2-3lbs of nitrous in the bottle. It was just that hot.
Just think of a pressure cooker: higher pressure=hotter food
