MPFI is fuel supply system technique which is used in gasoline engines. 

In this technique Carburetor is replaced by Injectors which increase this system accuracy.

MPFI stands for Multi Point Fuel Injection. In this technique individual injector injects in cylinder itself. 

In earlier time, it was done by carburetor only at one point from where fuel and air mixtures went to cylinders by intake manifold.

But now it is computer operated called ECU stands for Elctronic Control Module.