Hi. I have a 96 zj. When I bought it was misfiring on 1&2. I cleaned IAC. New plugs, wires, cap , and button, ran some fuel cleaner and 93 octane in it. After a couple days misfire and check engine light went away. About three weeks later the misfires came back. But now it is going from 1&2 to 2,4,6 I seafoamed through the intake. And smoke was pouring from the exhaust manifold. Could this manifold gasket leaking be my entire problem.? Any help is appreciated .