2000 Lincoln LS Ignition Coils
Mis-fires on my Lincoln LS. Two problems: 1 found oil around the spark plug boot. This was fouling out the wire. Oil was leaking around the valve cover and dripping down to the spark plug boot. On one side of the engine I replaced the valve cover gasket. On the other side, when this happened, I cleaned the top part of the coil over hole with carb cleaner and paper towel and then coated with red RTV before putting the coil back on. Both solutions worked. Too many times people replace the coils and don't do anything about the common oil leak. So if you see oil on your spark plug boot you have found your misfire problem.
2 Another thing to know about this engine on misfire is if it misfires only when the engine is warmed up then it could be a coil. The coils are enclosed in the head of the engine and operate at a high temp. Coils first sign of failure is misfiring at high temp. Because the engine OBD computer is not always precise on which cylinder is missing you may want to swap coils around to find the culprit. Replacing a good coil is not always the best so try to avoid replacing all of your coils only replace the bad one. A coil that has been working great for a long time is more likely to work good for even a longer time (explained by "infant mortality" ).