Are you sure the other ignition leads are ok? They can pass the multimeter test yet still be bad. They tend to be worse when hot. I had an issue with my TJ a few years ago. It started as a misfire at hot idle and progressed to misfiring under load as well as a hunting idle once. I ended up replacing the whole lot. Leads, cap, rotor and coil.

http://www.aussiemagna.com/forums/sh...746&highlight=