Originally Posted by EHarris

I just had the same code. I pulled #3 spark plug and there was a slight crack in it. Im not a mechanical person really. You can easily do this yourself. Tell them to forget about it and get your jeep back. Go to your local parts house and get a new plug (Champion double platinum is the standard OEM) pull the number 3 out and replace the plug. If it isn't the plug then its either the wire or the coil. I started with the wires first just because I was at 90k and I did plugs at 55k but never wires. Figured it had to be them. Nope. Cracked plug. Pull the plug, then try a different wire if you have an extra from the old set, then replace coil pack.

If its not one of these then post back and someone with better mechanical advice can help you hopefully.