Thanks! I'll replace it eventually, but my first priority is getting rid of that shudder. I'm really starting to think it's my torque converter. When driving to work yesterday, about 20 miles into my trip (i.e. warm-up no longer an issue) I gave 'er some throttle to get up to highway speed and then pass a car or two. Well wouldn't you know it, when overdrive kicks in (i.e. when the torque converter should "lock up") the car starts shuddering, although not as badly as when it's cold.
I told my dealer's service dept. about this, and they agreed that if the torque converter or tranny is shaking the car that bad, that it could cause the engine to misfire. They're going to look at it next week....