You only have one coil pack. It sets on the back side of the engine. A misfire is as simple as a bad plug or could be a plug wire or yes, the coil pack. How many miles are on your engine? I run Iridium plugs as they require less energy from the ignition system, thus less load on the coil pack. If not done recently, I would replace the plugs with new ones. I always change platinum plugs evey 50,000 miles and replace wires every 4 years regardless of mileage. I run OEM wires as for me, they are about the same cost as aftermarket wires. Easiest way to access the rear plugs and or the coil pack it to remove the wiper arms and the few screws for the cowling, then just pull the cowling out of the way. Opens the whole rear area of the engine compartment up for easy access. Ensure that you use dielectrical grease on all plug ends/wire ends to eliminate spark leakage.
2004 Freestar Limited 4.2 V6 w/Water Injection & Iridium plugs
2010 Lincoln MKZ AWD (Vacationing in Arizona)
2007 Focus SE (Just bought 9/29/2012 @ 59K miles)
1979 Gilson 32" 10HP Snowblower
2007 Generac 17.5Kw Generator w/33HP Twin-Cylinder engine
Farmhand 3-Cylinder air compressor
AMSOIL Lubricants and Filters in everything
"Have a good day, and a better one tomorrow"
Last edited by Use Common Sense; 02-13-2009 at 08:03 AM.