[Don C.]

I just rebuilt the top end on a 98 Gt 4.6, It had a blown head gskt. It starts up great but after about 5 min it starts to have a missfire, i drained the gas tank of old fuel, new filter. It idels great & has good power, but when you hold at a steady rpm you can hear the poping. But is on open headers.The fuel was old, when I pulled the plugs they were dark and smelled of raw fuel & it would load up and die and the smoke coming from the headers was fuel. the plugs looked good and where cleaned and re gaped, but I didnt replace theme could the overheating have damaged the internal parts of the plugs and the wires are on the right plug
Help!!!!!