scjmc,
I doubt you have PCM damage, though I guess it is possible. A slight missfire is not enough to trigger the PCM to trip a code. Now that it is "bucking" at idle, you definitely have codes set. I'm sure if you plug a scanner into the OBD2 port, you will get the cylinders that are mis-firing. The code will be a P030_, with the last number being the particular cylinder, (1 through 8). How many miles are on this vehicle? The "life expectancy'" of the factory coils, is 70,000 to 100,000 miles, depending on how hard you drive it. My LS recently stated dropping coils at 75,000. After the aggravation of replacing three that dropped within 2 months. I decided to replace them all. I did spark plugs at the same time. To me, the visteons are questionable. I went to O'Reilly's, (or whatever they're called in your neck of the woods), and bought the Borg Warner coils. They have a lifetime replacement through the vendor, not the manufacturer. Do yourself a favor, and replace all 8 at the same time, and plugs too. The missfire can foul a plug. Get at least Platinum plugs, and don't buy Motorcraft/Autolite. As long as your cowl seal, at the rear of the hood is good, LEAVE THE COIL COVERS OFF. All the covers do, is provide cometics, and trap heat from the coils, which shortens their life. You may also have an o2 sensor code from the missfires. Replace both upsteam o2 sensors if you have a code for one. This may seem a bit of overkill, but it will prevent you from crawling under the hood, or under the car, multiple times. Call it preventative maintenance. Hope this helps.
