Sticking Throttle???
 

Here's the problem. After I drive for a while on the highway at relatively constant speeds and then slow at an exit or whatever, the engine revs constant at about 2000 RPM. I can re-start the car and it idles fine, though. What could this be? I have lubed the throttle cable, but that doesn't seem to work. Any advice will be appreciated. Thanks!

Try cleaning your IAC (idle air control) valve with carb cleaner. Its the canister looking thing that is mounted at an angle on the front of your throttle body.

Also make sure your TPS has about .96.98Volts

right info but use fuel injector cleaner..it is less caustic and wont eat away at the spray coatin on the inside if it has any(started after a certain year cant rember)