Lets say my plug wires have 80,000 miles on them. Then lets say I took an ohm reading off of each plug wire and found that it was within Lexus spec. (Less than 25,000 ohms.) Then lets say I checked for spark and have spark on all 8 plug wires. Could I still have a bad plug wire?

 

yup, some of the sheathing could still be worn and arcing out when the wires are installed, easiest way to see is look under the hood at night with the car running