2000 Lincoln LS occastional miss

It's either the spark plug/wire, coil, or the fuel injector.

Pull the plug and check it's condition. Then install a spark checker. Remove the fuel pump relay and crank the engine. If the spark is weak or occasionally doesn't spark, then it's the wire or coil.

You'll need a stethoscope to check the injector. If you hear it clicking constantly, it's fine. If not, then it isn't firing. If the ignition system checks out and the injector is firing, you'll have to pull the injector and flow test it. (May be clogged)