A phenomenological model simulating stratification of temperature and species concentration was developed to predict engine misfire. The model incorporates the coalescence dispersion model for finite rate mixing and the mass entrainment model for flame propagation. The fuel mixture in the combustion chamber is divided into equal mass particles, each having a thermodynamic state. A first order chemical rate reaction for the combustion of propane in air is used. A set of ordinary differential equations for the evolution of temperature and species concentration for each particle is formulated. A predictor corrector method was developed to solve the system of equations.