The Mitsubishi 4A3 engine is a range of alloy-headed inline four-cylinder engines from Mitsubishi Motors, introduced in 1993 in the sixth generation of their Mitsubishi Minica kei car. It shares a 72 mm bore pitch with the 3G8-series three-cylinder engines, but has a considerably shorter stroke so as to stay beneath the 660 cc limit imposed by the Kei class. A 1094 cc version was made available in 1997 for larger cars, and was subsequently fitted to the Mitsubishi Pistachio, (and Pajero JR), a limited production car based on the kei class Minica equipped with the company's Automatic Stop-Go (ASG) system for cutting the engine when idling. So equipped, the Pistachio was able to record fuel economy figures of 30 km/L.

4A30

Displacement — 659 cc Bore x Stroke — 60x58.3 mm Fuel type — Unleaded regular gasoline

659 cc Electronic carburettor (1993)

659 cc SOHC (1993)

659 cc DOHC turbo (1993)

4A31

Displacement — 1094 cc Bore x Stroke — 66x80 mm Fuel type — Unleaded regular gasoline

1094 cc SOHC (1997)

1094 cc GDI (1999)