Thanks for the quick reply, I have been reading this thread and I am surprised that so many have experienced this and the dealerships seem to know nothing about the problem! Also, are there diagnostic codes that will show this as the problem over a supercharger clutch? I am taking the tech for a test drive Monday and I told them I wanted them to hookup their diagnostic computer in the car so I car show them a base line reading of when the car is working and then when it is not working, hoping to document the problem. but if no codes come up they will come back and say the supercharger is meeting factory spec, but I of course do not have that spec to show a side by side comparison. I can understand this causing the sluggish acceleration, but why would it keep me from topping out above 115 mph? Thanks again.