Hyundai Repair: 2001 TIBURON 2.0L, plug hole, scan tool

Question
OUR 2.0L TIBURON HAS QUITE A ROUGH IDLE AND VERY SLUGGISH ACCELERATION THAT APPEARS TO BECOME LESS NOTICEABLE AT HIGHER RRM, CHECK ENG LIGHT FLASHING.THERE IS 55K  ON ENG. THINKING OF MISFIRE ON ONE CYL I REMOVED EACH WIRE 1 AT A TIME. EACH TIME I REMOVED A WIRE THE CAR RAN EQUALLY WORSE ON EACH OF THE 4 PLUGS, I COULD ARC ABT 1/4 INCH FROM EACH COIL TO WIRE, IM THINKING THE COILS AND IGN ARE OK. COMPRESSION IS  150-160PSI. THIS IS A CONTINIOUS CONDITION THAT STARTED SUDDENLY UNDER LIGHT DRIVING CONDITIONS.

Answer
If your check engine lamp is flashing, you've definitely got a misfire.  If you've got access to a scan tool, my first recommendation is to see what diagnostic trouble codes are stored.  This will identify the misfiring cylinder.  I hesitate to tell you to drive someplace to have them read the codes for you because that may damage your catalytic converter.

If you haven't done so already, you could also check for spark by pulling the wires off the spark plugs.  I usually remove them all with the vehicle off and just place them back on the plugs without snapping them into place.  Then I start the vehicle and gradually lift them off.  In most cases, if a wire is arcing, lifting the wire off the plug will make it start arcing out the side of the plastic tube that goes down into the plug hole.  

But if the method I described doesn't work, you'll need to read the trouble codes since you haven't been able to identify the misfiring cylinder with more traditional methods.