i hooked up my nitrous, and changed my plugs to ngk's today but not with a full bottle it only had three puonds in it and at 600psi to test for leaks (direct port) now when i sprayed it was missfiring( ended up with a cel 43) could this be from low nitrous pressure and having too much fuel or could it be too high of jetting i only got it at 18/22

just guessing, i'm not sure of the engine codes. but i think that with that low of bottle pressure and only 3lbs in it i think you were just spraying fuel in and making it run to rich which might be your code. get your bottle topped off and get a bottle heater to bring up your pressure, that should get you going.