welp i've had this problem before and i cant remember the the mech. told me it was something to do with the intake manifold or a dirty sensor. But i have a 95 honda civic, d16z6. The problem is when i drive than put the car into park yes its a auto it revs up and down a lot. i dunno what the correct termenology would be for that. if you've ran into this problem what steps did you take to fix this.

 

I had a similar if not exact problem. Check your linkage that is connected to your throttle body and make sure every thing is not too loose and not too tight, then check the actual throttle linkeage that is gong in to your fire wall of the car, make sure that it is fastened tight in there, I think you have to turn it like a key in order for it to lock in there.