Make: Holden
Model: Commodore, VS
Engine: V6 Ecotech
Year: all

Engine miss under load or at highway speeds.
Leads for drivers side plugs cross-fire inside plastic tubing (where leads cross the valley). Check of lead resistance does not reveal problem. Has been observed on O.E. and low quality aftermarket sets, but so far not a known problem for Magnecor leads.

Remove drivers side leads and examine closely (for full length, including inside the plastic tubing) for signs of arching (light grey or blue-grey marks) and replace as needed.