1998 ford escort running with a miss in it put new plug and plug wires on it and a new fuel filter Still has the same problem?

Is it a very regular single cylinder misfire? Are the new wires properly installed? Do you have spark voltage to the plugs? If no spark, check the ignition coilpack.

If spark is good, check for leaking intake manifold gasket. Spray a bit of carburetor cleaner along where the intake manifold mates up to the cylinder head. If spraying changes the sound of the running engine, you need to replace this gasket. When spraying, be careful not to set a fire, especially if the engine is hot.

Is your computer able to control it's idle speed? Sometimes a bad IAC will cause the idle speed to be very slow and give the appearance of misfire at idle.

Do you have a disconnected or dead fuel injector? Once you determine which cylinder is misfiring, monitor hydrocarbon emissions at the tailpipe. Unplug that fuel injector and note whether or not unplugging it causes a dramatic reduction (from absurdly high to reasonable) in HC emissions at the tailpipe. If no change, that injector wasn't working. Check for electrical pulse at the connector and if present, replace injector. If pulse not present, check for power on one wire (should be 12V+ with key on). If no 12V+, repair that wire. If no pulsing 12V-, check for lack of continuity to PCM or bad PCM.

All of this assumes a fairly regular misfire. If misfire is irregular/random check for vacuum leak or damaged MAF sensor.