So my 91 mustang has a powerdyne supercharger and it’s been on for a few years now. I rebuilt it a couple months back after a weird noise in between shifts and after the rebuild it’s been fine up until now. So the problem is when I have the supercharger belt on and under tension I can feel a vibration or a shutter when letting the clutch out. This only happens when comming our of first and second and also in 5th gear at highway speeds you can feel a noticeable vibration like something is spinning un-even. I noticed this started to happen only after removing my transmission mount to add the mid-pipe hanger. After that the car threw off the supercharger belt and I didn’t notice until the next time I drove the car the shutter was gone but I wasn’t making boost leading me to find the charger belt had been thrown off. Now without the charger belt on the car feels fine no symptoms. Now I’m not sure if the charger is the problem or if it’s making the problem more pronounced. My first thought was the balancer but it looks in good shape visually but I’m not ruling it out. Cause I can see the crank pulley has a slight wobble to it but I’m not sure if that’s just the engine itself goin back and forth ever so slightly . The drive shaft u-joints are only about a year old so I don’t think that they are to blame. Any insight would be great. Thanks