What would cause my RPMs to jump while braking?
 

My 02' SL2 rpms jump when i brake from a moderate to high speed. The rpms go down to 1800 rpms back up to 2000 like the car is revving. Could this be a stuck throttle or something else?

If the throttle is stuck why would rpm's increase? If stuck is what it is, nothing should change.
Out of curiosity I would try putting the car in neutral and then applying the brake to see what is happening but on the whole if applying the brake is causing the problem that something moving when the brake pressure causes the car to slow down.
Like maybe the engine is rotating pulling on the throttle cable. In that case it seems to me that something like that should happen if the transmission was in neutral and you applied the brake.
If he engine/transaxle is rotating I think I might look at motor mounts to see what is going on.

I agree with unc about checking the motor mounts. They may be broken and causing the engine to shift and pull on the throttle cable.