It could be but you must realize that unlike the old single coils that worked with a distributor, this system has three individual circuits, and each one includes two spark plugs, two spark plug wires, the coil's secondary winding, and the cylinder heads to form one big loop. A break anywhere in that loop causes current to stop flowing and there will be no spark at either plug. That means one open plug wire will cause a loss of spark at both spark plugs.
To start with, measure the resistance between the two spark plug wire terminals on the coils. Compare the two that are working to the one that isn't. If there's a significant difference, suspect the coil pack. If they all measure about the same, the non-firing coil could still be arcing internally. To know for sure you would just have to try a new one.
Another trick is to disconnect both plug wires at the coil, then fashion a spark gap between the two coil terminals. You can bend up two pieces of wire to sit in each terminal with their ends almost touching each other, with about a 3/16" gap. If you don't get a nice solid spark while cranking the engine, replace the coil pack. The preference is to not use just one piece of wire to do that. With one end anchored in a terminal and the spark jumping at the other terminal, carbon is left behind by the arcing, and you don't want that carbon to be at the terminal. Carbon is a conductor and can short out the spark after the original problem is fixed.
If you have a scanner that has the automatic test mode feature, you can use that to cycle the individual ignition coils on and off so you don't have to crank the engine to do the testing.
Sunday, January 20th, 2013 AT 2:18 AM