If you suspect missing at idle, loosen all the wires at the cap while not
running. Then start it and using gloves and an insulated pair of pliars pull
one wire at a time, it should lower the idle or even stop the running.
If you pull one and it makes no difference you've found your miss.
At that point switch the wire with a different cylinder,and test again.
If the miss is now where you switched the wire to then the wire is bad.
If the miss is still at the same cylinder, check the plug and
dist. cap inside for that plug.
You can also hook up a timing light to each wire and watch it flash
to isolate the missing cylinder.
