revs to 2500 and does not drop to normal

Abnormal strain on your drive train will be realized until you settle the idle issue. Avoid putting it into gear for now. Sounds like a sticking idle air control valve, a faulty throttle position sensor, a vacuum leak... A diagnosis really needs to be done to find out what is going on.

i would check the vacuum line right in front side of TB just to right slightly on base. should be at 5 o'clock when looking from front of grill. that hose popped off on my other car and it caused the idle to do the same. i ran it like that a couple times and i bet like me, you hardly have to touch the gas pedal when you get on hwy right????? if not that try the TPS or IACV