Syngas produced from biomass fuels is studied for renewable energy in combustion engines. Syngas used in dual fuel modes can reduce diesel consumption in diesel engines, but exhaust products are increased. Exhaust gas recirculation (EGR) can increase fuel efficiency and decrease exhaust emissions. Therefore, the research aims to study the performance and emission of a diesel-engine generator at 3,000 rpm and various loads, fueled with dual fuel modes by adding syngas, air, and EGR. Syngas was generated from wood pellet by a downdraft gasifier. Flow rates of syngas and air were added at 93 lpm and 86 lpm, respectively. EGR was expanded from 0.36 to 1.92 lpm. The best engine performance in dual fuel modes was found at 3.82 kW. The increase of syngas, air, and EGR flow rates led to the changes of engine performance and exhaust products. Regular diesel combined with syngas-air-EGR blend by increasing syngas, air, and EGR at 93 lpm, 86 lpm, and 0.84 lpm led to the addition of engine performance and the reduction of exhaust emissions. Outstandingly, carbon dioxide, carbon monoxide, nitric oxides, and particulate matter were decreased by 2.98%, 10.08%, 12.64%, and 2.60%, respectively. The regular diesel saving was raised by 43.33% compared with the mode of only regular diesel.