It cranks over but will not start, acts as though it's flooded. Lean is just a guess really, I do have an aftermarket AF gauge however, it reads from the O2 sensor and is reading VERY lean as were before the swap was reading perfect (as in right between rich and lean). Yes, it is a Nitrous Kit however being an EFI kit, it is a dry kit which uses a solenoid to up fuel pressure and only shoots Nitrous into the throttle body. The fuel filter I have replaced and the car has 93 Octane in the tank.