started up the car earlier today only to hear a knocking noise coming from engine,its ok at idle but when turning key to start you can hear knocking and around 3k revs and up you can hear it.its not noticeable when sitting in car but with hood open can be herd plainly.the car is a 96 na with low miles and running on all cylinders and not over heating. not much history on car and haven't it long.i know when i got it i checked it for oil and there was a good bit to much oil in it,did that cause damage i wonder?thanks for any help

Worst case scenario? Bottom end bearings knocking does it get louder and the speed increase when the revs come up?

ya it gets louder when the revs increase alright,is it a big job to do bottom end bearings?cost?engine out anyway i guess! probably better off not driving car till i get it looked at..