[silicon212]

The "burning rubber" smell is probably oil dripping on the exhaust manifolds from leaky valve cover gaskets. Don't try to tighten the bolts on the valve covers to seal it better - you'll only distort the valve covers and create a huge leak. Replace those suckers!

There are two idle adjustments on the E4ME Quadrajet that's on that car. One is the curb idle speed adjustment, which is on the passenger side of the carburetor, above the choke. The second one is the idle speed adjustment, and that's on the driver's side at the front, about midway down the bowl. It's pointing directly front, and you'll need a T15 Torx driver to adjust it. In some cases, a flathead screwdriver will work, check to see what you have. There's also an adjustment for the idle stop solenoid that's also on the driver's side of the bowl (the idle speed adjustment screw hides behind it). You can adjust this in a little if it's the cause of the high idle speed. As for a "clunk" when engaging drive or reverse, that's usually an indicator of worn U-joints, or more rarely, wear in the differential.