Fuel heater?
 

We all know that warm fuel vaporizes better than cold fuel, so I had an idea. I want to make a fuel heater for my Civic that uses coolant to heat the fuel. My Civic has a returnless fuel system, so a fuel heater won't heat the fuel in the tank. I think a fuel heater could possibly improve gas mileage by improving fuel vaporization, especially in cold weather, but I'm not sure. I don't really think that building a fuel heater would improve anything, since all the car companies would probably be doing it if it would, and I probably am not the first to think of this. Can't hurt to ask though, right? What do you think about me making a fuel heater?

For winter use only, might as well.

It wont hurt, but probably won't help too much either. OEMs kind of do this already. With port injection engines, they typically aim the injector to spray onto the intake valve which is quite hot to help vaporize the fuel. In throttle body injection which is pretty old tech theses days, they warm up the throttle body to help vaporization through the intake manifold similar to a carburetor. Direct injection I don't think warms things up, but its being shot through tiny injector holes and injected at massively higher PSI than the others. So vaporization is less an issue, plus being injected right into the combustion chamber helps vaporize things quickly.

From reading the service manual, i found my car ('15 mirage) has a fuel temperature sensor so i feel it must have a worthy impact or OEM simply wouldnt bother

Not necessarily. Temperature effects the density of the fuel, which is likely why it has the sensor, but the density of the fuel will obviously effect how much fuel the engine needs to run at a certain A/F ratio. The same reason why the car has an air temp sensor in the intake.

Edit i just realized a huge hole in my theory