Vibration/buzz from engine compartment

As the engine in my 2002 tracker reaches enough rpm's to shift into the next gear (automatic tranny), it makes a buzz/vibration (like an exhaust rattle) sound, but disappears instantly when the tranny actually shifts, then comes back as it nears the next shift. I can also make it do this as I make the rpm's go up, even without shifts. So, I know its not the tranny. I sounds like exhaust or exhaust shield or something. Its coming from underneat the drivers side and at first I thought it was just a spedometer cable being rusty but I think I have that problem also. I can hear the other noise if I listen outside the car with the window rolled down. You can hear it coming from underneath the car. Sometimes it doesn't do it as much. It seems to do it only at a specific rpm and then the rattle stops. You don't hear it at all as the engine levels out on the road.

Any advice?

I have had the same thing for the last month or so. I noticed it happening when I first start up when the engine is cold and the rpms are slightly higher. It's not the rear exhaust. Also pulled/pushed just about everything under the hood looking for something loose. Next step is to get underneath and see if anything is hitting.

I haven't noticed any power loss or mileage change. I'm due for a tune-up soon so, maybe that will help.

Mine does the same thing. But I know mine is the cat. converter heatsheild. It does the same thing yours does, Mine vibrates from 1900-2100 rpm. Man it's imbarrasing

I've heard that 2002's have a known problem with the Y exhaust right at the engine, cracking slightly. If it was under warranty they would fix, but if not, they definitely won't.

Finally crawled underneath and low and behold... The heatsheild on top of my catalytic converter is rusted and loose in a couple of spots and creates a nice rattle when I bang on the exhaust pipe with my hand.

Anybody have a part number for it? Or should I just bend some sheet metal?