Ding, ding, ding....correct! This is why TBI did not last all that long on OEM engines. Couldn't get to PFI fast enough! Getting air distribution on an intake is hard enough. Getting the wet fuel flow in addition to the airflow is a whole 'nother world of development. So if you can get the air dist acceptable, then just shoot the fuel at the intake valve (PFI) and you'll be quite a bit ahead. (Of course, how to position/angle the injector is another significant development piece of work.) Or better yet, just inject the fuel into the chamber (direct injection or DI). This was done to increase the power output as the fuel no longer takes up the volume with the air going through the port/into the cyl (i.e. better volumetric efficiency), and there's no worry about fuel flow/distribution. DI also allowed the CR to be increased as the heat of vaporization also helps cool the chamber further enhancing fuel efficiency and power. And then you work on piston topography to get the flame propogation required to meet the emission standards required. Fun,fun, fun! And then...