I was driving two days ago and a accelerated to merge. In doing so my car was very sluggish to respond and my CEL began to flash. Luckily I wasn't too far from home. I then pulled the code P0301 which was causing my CEL, misfire in cylinder one. I started the car again and the misfire was very noticeable at idle but at 2000+ rpm it seemed to vanish, I assume this is due to the momentum of the other cylinders compensating for the tremble. I then took out the spark plug. I noticed the smell of unburnt fuel and the huge gap , .060+. I replaced the spark plug and cleared out the code. Instantly on start up the code resurfaced along with with the tremble.

My next step is to replace cylinder one's ignition coil. Hopefully this will solve the problem.

My question is... How common is this occurrence? Is it likely it is the coil or could it be something more severe?

 

Clear the codes, swap coils with cylinder 2, see if missfire follows it. If so, change the coil. Use a little caution pulling the coil loose. They have a flange with a odd shaped square-ish O ring. Prior owner had snapped flange off of several coils on my car. I'm sure you'd rather not break the flange on a good coil. Many places that sell the coil, don't include the o-ring, so you may have buy o ring separately, or reuse old one as alternative.

 

This^

Also keep in mind the newer 2.7 03+ used different coils, to which it may not apply (o-ring)

 

Okay it was a bad coil for cylinder one. However, I believe the extreme gap on the spark plugs is causing too much stress on the coils and causing them to fail. Today, I am going to change all the spark plugs and gap them accordingly.