Fuel Injection does (did) exist for RC car engine's. It was stopped due to patent rights from the company that licensed it.

http://www.pcrcproducts.com/news.html

Basically the unit monitors exhaust temperature and adjusts fuel flow from the injector pump to maintain a given temperature. It works great, and run times are increased due to higher efficiency.

I have one unit available that has been serviced and has a brand new injector pump. The computer module, leads and temperature sensor are all in perfect condition as well. Instructions included.

I will sell it for $175.