
If it is pouring liquid out the pipe you have a problem, maybe the fuel cap is not venting properly or something. All EFI cars pressurise the tank to a certain degree as the return line itself is pressurised. Gottta love that whistling sound on a hot summers day. But to be pouring liquid out one of my guesses is that your fuel lines are restrictive and while the pressure going into the tank from the return line is "normal" for an injected car the fuel pump itself is either not recieving enough (doubtful as the car runs and I am assuming very well) or the line after the fuel pump is restrictive lowering the pressure difference while not affecting performance.
Also the carbon cannister is for vapour only. It will not retain liquid petrol.