Possible vacume leak

i own a 00 chevy cavalier z24 ive noticed it started to lose power it has 90000 on the motor. i am experiencing high rpm’s when shifting from gear to gear, meaning when going from 1st to second the rpm’s will be at say 4 grand when engaging the clutch to shift i need to hold the clutch for more than a few seconds to drop the rpm’s to shift into second with out allowing the car to buck because of this. you can also hear a slight sound almost like a turbo without the turbo lol. what can this be. this happens in every gear. its not normal for i have drivin a standard all of my life.

A clutch that won’t disengage due to a lack of brake fluid in the clutch master cylinder is one thing. The other dandy one is if the transmission oil has leaked out.

you sure a z4 isn’t a cable clutch? I’d say you need some professional help, there are too many possibilities here.

this car is not a cable clutch for sure but what would cause the rpm’s to stay up when clutch is engaged

Have you inspected the throttle cable, linkage, etc, for physical binding or obstruction to free movement?

Perhaps the cable is hanging up, or the throttle itself is sticking.

just for a few seconds i manually reved it up from under the hood and found no binding at all however that does not explain the hissing sound when i press the clutch while trying to shift

When no cars are around speed up in 3rd gear, say 5-6 grand and just when you start to take foot off pedal pull shifter into netrual without clutch and if revs go down fast you know it has nothing to do with clutch.

while you all are offering great suggestions no one has yet to suggest the hissing sound when shifting. any suggestions on that?