Ok, 1997 Bonneville 160K, This all started when a Check Eng light came on for a cylinder 4 misfire. Shortly after the supercharger started to make noise (similar to a meat grinder!). Now it will jerk and stutter when you give it more than a touch of throttle. The boost gage will peg out into the yellow and the tranny hesitates to shift unless you back off the gas. I have done a complete tune up (plugs, wires, PCV, air filter and oil) with no change in performance. I have pulled the SC belt and the vehicle will run through the gears without incident. So I'm leaning away from tranny trouble. A miss or any misfire is not apparent at idle or in park or neutral. Some are saying it'* a bad coil pack, CAT, or the Supercharger is just done for. Any advice?? My ride to work is getting interesting to say the least.

Use this procedure in techinfo on checking your coils.
http://www.bonnevilleclub.com/forum/...e=article&k=33

The supercharger is a very reliable item, so that is not likely to be the problem. Some parts of the supercharger could need replacement, however. Take the drive belt off again, and then check the pulley for any looseness. Turn it back and forth to see if there is any free play. Also, move it up and down, as well as in and out. Any looseness?

Check all of your vacuum hoses for any leaks. Are you losing any coolant? Check both the expansion tank, and the radiator.

I check the pully when the belt was off. Everything seems fine, no play and spins freely. The noise coming from the SC only comes when the it starts to jolt upon acceleration. Also a hissing noise accompanies the stuttering. Have any other suggestions? I'm really stumped here...

I think you should check your PCV valve. With those simptoms and the "hissing" noise from the SC that'* where I'd start.

And really do check over all your vacuum lines very carefully for any splits or cracks, including those that go under your airbox into your evap. cannister.

Also check your EGR tube for cracks or holes.

It almost sounds like you have a good sized vacuum leak. This is a free diagnostic and an inexpensive repair if that'* what it turns out to be.

First off, thanks everyone for all the help so far. But, I checked all the vacuum line and replaced a bunch of old cracked lines. So no more vacuum leaks that I could find but the vehicle is still performing the same. Dose anyone know how to test the Boost Actuator on the side of the supercharger. Or if there is a pressure limiting switch of some sort that may be acting up? I really don't know much about super chargers to trouble shoot it. Also is there any type of kick down system that relates to the transmission that might be out of whack. Any info would be greatly appreciated.

Let'* hold off on diagnosing the supercharger actuation. At this point..your symptoms don't lead there.

Your symptons are pointing more toward sensors or gaskets. Have you pulled any of the plugs and checked them for any fouling?

Cleaned any of the throttle body sensors?

At 160,000 I would want to look for signs of a lower intake gasket leak if the gaskets have never been replaced, also cleaning and checking sensors. Let'* get all the free tests out of the way that we can. Also if you can get the car scanned for any Diagnostic Trouble Codes for free at a parts store. With all the symptoms it'* exhibiting, I'd be surprised if there wasn't at least one stored code. (Not all codes turn on the check engine light).

OK! We are all fixed. After all my bumbling around one Catalitic converter was the problem. After holowing it out today the car runs better that ever. Thank you all for all your help.