First off I would check the plug wire & dist cap on #5 cyl. The wire should have no more then 10,000 ohms per foot of length. If you don't have an ohm meter change the wire with another wire & see if that changes the miss to the other cyl. Examine the inside & outside of the dist. cap for carbon tracks or cracks around #5 term. Check the spark plug for cracked porceline.
George
