Okay guys.... I'm kind of going through the same thing as gthmcty1 was going through in his post about the knocking noise. I have a 1985 cutlass with a 307 in it & I hear the noise on the passenger side when my car is idling but it goes away when i press the accelerator. The car starts/drives fine. What could this be. I'm going to check everything you guys said to check in the other thread. Any other things I should check?

 

Could be a minor exhaust leak. I've had a problem with the A.I.R. tube that goes to the converter on the 307s. The rubber hose that connects the tube to the converter goes bad, resulting in a noise at idle that goes away as the RPMs increase. Other things to consider are the A.I.R. pump and the exhaust manifold on that side.