Tony,
I held the clutch in for 4 or 5 seconds. Don't know if that was enough to go to idle but it did decelerate a good bit, and the vibration continued.
The more I think about it, the engine had to go to idle. Even at 85 mph in overdrive I'm only about 2780 rpms so it wouldn't take long at all to drop to idle (around 800-1000 rpms, I'm guessing).
I'm almost completely convinced now that it's the driveshaft. But then again I've been wrong before. :p
Many times.
-ftyler
