New Gas Tank Issue

Morning, Gang! Just recently had the fuel tank replaced on my '03 Pre-Runner due to corrosion. The tank installed like a glove but there seems to be an issue with filling it up now. I can't pump gas faster than a quarter of the speed that I normally do without the pump nozzle shutting off. Looking around the web, it seems to be some kind of problem due to vapour not escaping and telling the nozzle that the tank is full. I called the place where I bought the tank to ask them if I had forgotten to purchase anything extra with the tank that was needed but they told me that the tank they sold me was complete and that nothing else was needed. I'm thinking the mechanic who installed it might have inadvertently blocked the vapour escape hose or something may have gotten saturated with fuel when the old one was removed. It's not one of those "end of the world" problems but a pain nonetheless. Any thoughts as to what might be causing this issue? Thanks!