"Jay Honeck" wrote in message news:cI9od.66570$V41.11973@attbi_s52...
Our JPI EDM-700 engine analyzer may have paid for itself today.

Here's the scenario:

snip

Your tests have pretty well narrowed it down to a plug that isn't
firing (the 1st thing I look for when EGT shoots up on one cyl.).
It's unlikely that the mag is firing well on all but one cyl. The
most likely causes are a plug wire or the plug itself. If your mech
is equipped with good testing gear, he should be able to isolate the
problem pretty quickly.

John Galban=====N4BQ (PA28-180)