My civic is a 93 with a d16 in it also with a turbo..

okk so heres the problem. when ever im driveing and it gets around 4000-5000 rpms it just starts to rev. untill it get back down below that. i was wondering if it was the transmission or what?

anything will help right now thanks!

If it's manual, sounds like your clutch is slipping. The engine revs up but the car doesn't go faster. Does it smell like burnt brake pads under the hood after it does that?