I have a 2005 Chevy Cobalt SS (2.0L supercharged 5 speed manual) with 128,000 miles. I can hear a vacuum leak, the brakes are spongey, and when I press on the brake I can hear the idle change so I thought I might have a leak in the brake booster because my vacuum line for the brake booster looks fine. I tested this theory by starting the car, clamping the vacuum line for the brake booster, shutting the car off, and repeatedly pressing the brake to see if any pressure leaked out. However no pressure leaked out. Im not sure whats going on but I think it’s also affecting my clutch, sometimes the biting point will change and right as I let the clutch out it will bite. I’m not sure whats going on please help. Btw my brake booster vacuum line is connected directly to the supercharger.