In this study, a comprehensive two-dimensional gas chromatography was employed to analyze combustion products in exhaust gas emitted by SI combustion. From the exhaust gas analysis of SI combustion which used regular gasoline and 10W-30 lubricating oil, a lot of peaks which include many compounds produced by lubricating oil were detected. Therefore, n-heptane as fuel and poly-α-olefin as lubricating oil were applied for engine experiments. From the analysis focusing on linear and branched oxygen containing hydrocarbons with seven carbon atoms, it is suggested that many types of oxygen containing hydrocarbons which is not considered in detailed reaction model exist in exhaust gas.