I have a 99 WS6, 6 speed with 85k on it. Everything on the car seems to be smooth, love the vehicle. However, I am getting a little freaked out because the car will seem to hesitate about halfway through the gears sometimes. The engine accelerates as if nothing was wrong (I believe), but the vehicle lags in acceleration, almost as if the clutch was pushed in, but will then "catch" and continuing accelerating like it should. This problem is not constant- it does it from time to time, randomly, and through random gears. The engine does not scream or over rev when this happens, so I don't think its the clutch slipping.

PS: Would a bad MAF cause some kind of wierd acceleration or hesitation? The car used to have a K&N so I wonder about the oil.

I have no idea what this is, and like I said it varies from time to time, but definately worries me. I wonder if it is transmission, or rear-end related, or if its not drive-train but rather MAF related??? Thanks for any input.

Sounds strange alright. Seems as though if it was tranny or rear end related it would be more consistant. There's so much electronics that can affect performance like that, it would be hard to say is maybe a wire is loose or almost broken but seems like it would throw a check engine code. You might could get a shop to run a diagnostic check on it for a reasonable price. That would probably be the best route to go.