With all the cool after market DeTomaso valve covers and air cleaners, sometimes people get confused when they are installing these parts and forget about the fact that the engine must breath. If you car has be upgraded with these parts make sure that one valve cover, usually the left cover has a working Positive Crankcase Ventilation (PCV) valve that is connected to the intake manifold vacuum source. The right side valve cover should have a hose connected to the filtered air side of the air cleaner to supply air to the crank case. The air path is from the filtered air side of the air cleaner to the valve cover on the right side of the engine, through the engine, out through the PCV valve and into the intake manifold.