When my car is in overdrive and i let off the gas, say to stop at a redlight the motor revs up and down for 5-10 seconds. anyone ever had this problem?

 

hey..it sounds like your Opti could be a possability...hopefully not though. Not cheap and not fun (the first time anyways )
Just an idea..my 94Z did that..at idle and got slightly worse over a few weeks where it would 'surge' between 1500-3000 rpms as i shifted (6 spd). It ended up being my Opti-spark (distributor).
You could always find someone with a diagnostic thing to see where your problem lies...there are probobly a number of things it could though..worse case..Opti..hope its not man, good luck