95 continental running rough/misfire

I just recently bought a 95 continental and love it! It was great the first few weeks but then I noticed the fuel economy started to go down. But I had just realized that it took premium fuel where as I had been using regular. When I switch to premium is when the fuel economy went down. So I switch back to regular and the fuel economy stayed bad. Then the engine started to run rough and finally the check engine light came on. I scanned it and it said it was a misfire on cylinder four. I replace the spark plug and measured the resistance on the cables, which seem fine. I check the coil resistance but am not sure I did it right. Any advice on how to check the coil or any ideas on what else might be the problem? Thanks all.

Check some of these Tech Articles (http://www.lincolnsonline.com/tech.html) to see which apply to your Lincoln.

Chances are you may have to deal with several issues.

I have the same year same model same problem with number 2 cylinder. I was told it could be a stuck fuel injector. I haven't had a chance to try and fix mine yet. I hope that's all it takes because after the plug, the wire, and the injector is the camshaft.