Plugs where replaced at 18000 and at 54000 I did tests. The mis-fires not really noticed or felt. Unfortunately as an everday driver the type of driving is not following a routine.
And a lot of short trips and errands mixed. Out of work/early forced retired and baby-sitting the grandson. Then the occasional trip (500 mile) to visit the other grandson Rockford, Il.

Really hard to get a good feel when I don't get to drive daily.
Thank heavens for the OBD 2 & Ford specific tests.
These misfire tests are recently new as far as Alex updated his software and the info released by Ford is not explained.
http://www.motorcraftservice.com/vdirs/retail/default.asp?pageid=diag_theory_retail&gutsid=diagsheet&menuIndex=18
This is the only source I could find. Mine is 98.
If you are inertested look at the PDF Misfire monitor section.
Bottomline my counts are all zero so I figure that as good as that will get, regardless what all the different low level or high level. Its really neat how they determine a misfire, though!
Paul

Paul 98 Mystique LS 2ea (07/97)(08/98)