Environmental contamination poses a real threat to the environment and all organisms. Air pollution has increased markedly due to an increase in human activities and petroleum use for electricity generation, transportation, and industrial applications. Internal combustion engines play a significant role in society’s health and power requirements. However, automobiles are the main source of pollution and NOX emissions. This work presents a study of the performance and exhaust emissions of an internal combustion engine fuelled by gasoline available in the Saudi Arabian market, RON91/RON95, with an admixture of syngas and 5% by volume pure ethanol (E5) in the presence of different ultra-lean mixture regimes, including λ=1 for a stoichiometric mixture. The studied ranges were λ=1.13, λ=1.26, λ=1.43, and λ=1.67. An entirely automated engine and plasma converter system was developed for feeding the same type of fuel. The engine was modified for a more efficient operation by introducing a plasma-based fuel reformer. Syngas was produced through the partial oxidation of gasoline with air in a plasma-assisted fuel reformer in the presence of steam to reduce the amount of soot formed in the plasma reactor. The fuel consumption and related emissions were measured. The experimental results demonstrated a significant total reduction of NOx emissions compared with those from the original engine. The most obvious reduction (approximately 50%) of harmful pollution was observed under lean conditions, and the total gasoline consumption (including the gasoline required for the plasma-assisted converter) slightly increased. The results also showed that the NOx content for these new blends was lower using E5-gasoline 91 than that using E5-gasoline 95 and was generally lower using E5-gasoline 91 and syngas than that using E5-gasoline 95 and syngas.