Exhaust Smell in Cab: If an exhaust smell is present in the cab, inspect for leaks at the exhaust manifolds. Ford's procedure calls for warming up the truck to operating temperature, then shutting off the engine, remove the EBP sensor and use a smoke machine to feed smoke into the exhaust system. Inspect each exhaust port, manifold flange and Y-pipe joint for smoke leakage. I find using a length of hose as a stethyscope while the engine is running works well to pinpoint exhaust leaks. If a leak is found at the exhaust manifold, replace only the manifold gasket that is leaking(I think this should read INSTALL a gasket, since originally there are no gaskets at the manifolds). Gasket P/N 5C4Z-9448-A. TSB 05-13-9.