Just the other day my car ('95 Z28) started making this knocking noise... It gets louder as you go through the gears, with the exception of 5th being a bit louder than 6th. It only makes this noise when giving gas, and the more gas you give it the louder and faster the noise is. The only thing I can think of is that I went up a small ramp the other day and scraped the tail pipes... is it possible I did something to the driveshaft? Maybe the transmission is taking a dump on me?

Nothing seems loose on the car anyway, exhaust-wise.

I figure I'd ask around here before I pay an arm and a leg at the shop.

 

My first guess would be the tranny mount. Look on the back of the tranny...there will be a big rubber thing. See if it is broken. Easy way is to see if you can push the tranny up.