The objective of this study is to analyze and predict the flow through the intake manifold using a computational fluid dynamics program (CFD). The performance of internal combustion engine depends of the intake manifold and its components. Three model of the intake manifold flap was created and analyzed by using the commercially available ANSYS software. The volumetric efficiency which affects the engine power and torque is affected by the flow of air in the intake manifold. These paper reviews the work realized by various researchers in the field of variable intake manifold. The CFD plots offers valuable information’s of the flow field and tension distribution in the various part of intake manifold flap mechanism. The results show that the CFD model can be used as a tool for improve and optimize various part of the intake manifold flap.