Considering all the costs involved
if it were mine
I would install new OEM spec sparkplugs
and set the gap relatively small
like 0.025 inch
as one simple way to minimize the miss.
While changing the sparkplugs
as a minimum
I would use the ohms range of an electrical multimeter to check each ignition wire, then divide the Ohms reading by the length in feet of the particular ignition wire and be very suspicious of any ignition wire that had a high or low value for Ohms per foot of wire.
To find a random miss
you really need a meter like this one:
http://www.etoolcart.com/index.asp?PageAction=VIEWPROD&ProdID=5073
but if on a budget
it is at least possible to use a
inductive clip on timing light
and move the inductive clip from wire to wire
watching the 'steadiness' of the flash rythmn
to find the cylinder with the miss
Low compression in one cylinder
due to a bent valve/leaking head gasket
is a common cause of miss-fire
when everything in the ignition system
checks out normal
Good luck
