Q: Leak in manifold

Intake and exhaust manifolds do not effect each other. If you had an exhaust manifold leak then you will hear noise but it should not effect the way the engine runs. If you have an intake manifold leaking then your engine may run rough and may cause coolant and vacuum leaks. The exhaust on these engines may leak near the head causing the manifolds to warp and need replacement. The intakes have problems with the rubber gaskets and may leak vacuum or coolant. I recommend having a qualified mechanic, like one from YourMechanic, come and inspect the noise coming from your engine.