My car starts off fine but when i rev the engine and it hits 2000 rpms it keeps going over 3000rpms without me accelerating anymore i have no idea what the problem is someone please help.

 

Get your head under the hood and locate the throttle linkage. Start your engine and manually manipulate the throttle to ensure that it's free and easy and not sticking. If it's dirty or rusty, clean it up. Force it to the idle position, check that it stays there and see what you read on the tach.
If it still takes the bit between its teeth, you may have a hung up IAC (idle air control) system.