what is mpi?

MPI usually stands for Multi-Point Injection. Most modern cars have this. A lot of older small engine cars had SPI (Single Point Injection), a lot of car manufacturers don't advertise MPI as much these days which is probably why not many know of the abbreviation.

To see which one is in that car,you need to take a look to the intake manifold.MPI,Multipoint injection will have same amount of injectors as there are cylinders.Injector is mostly "plastic stick" on intake runner that has wires coming out of it.If the car is SPI,then injectors will be most likely to be found under the air cleaner.Spi will "fire" its injector's at once every time 1 of the cylinders are at top dead center.MPI will only fire injector on that particular cylinder,not all at once.It is more precise way to feed fuel to the cylinder's therefore creating much more cleaner burn,and more effiency from the motor.That's why it helps on gas mileage.