I have 99 mustang with a V6 that runs good and strong. BUT... Once it warms up it starts making a noise, a tapping or a knocking noise from the engine. Asked a better mechanic in my family and he said that I need to replace the exhaust manifold gaskets and it'd fix the problem. Since this is one of my first Ford vehicles I'm not entirely sure if that'll fix the issue. Anyone have any ideas as to what it is? Please let me know.