so ill start out saying this is my first post. me and my dad are trying to get his 96 stang running right after it was stolen (for the third time). its got over 450,000 miles and on its 3rd motor with about 50,000 miles on it. It was running pretty rough when we first started up after about a year, but we changed the filter and oil which was black but didn't look like antifreeze in it (great), new air filter which was disgusting, new thermostat, new pcv sensor, and it sounded better but had a misfire. we looked at the coil pack and it had a crack in it where the plug goes in (not the plug wires but the plug on the side) so we moved it back into place and super glued it to where there is no misfire anymore so it is fixed till we have time to get another one. we drained the antifreeze and it was brown so we are guessing it was rust since there was no white smoke from exhaust, no bubbles in antifreeze while in radiator from an air leak from a leak in the head, no over heating, and no smoke coming from radiator. so we flushed it out using a flushing kit till the water was clear and antifreeze has stayed a bright green color. so it was running great until we changed plugs (which all had a great color on them) and it started ticking from the passengers side valve cover so we took the plugs out just to make sure one didn't get thrown through the head like ive heard happens to 4.6s and they all came out good and went back in good. we di have a problem putting the front most plug wire onto the plug and it still never clicked into place like the others but it is seated better than the other so could this have something to do with it. so im wondering what this could be. sorry for the book ive wrote but i tough it would be easier to troubleshoot if you know what weve done