No a bad egr will cause surging at idle or bucking while under light acceleration.
Something Loose?
Rattling under the hood can be something easy to fix to something bad. It could be loose bolts, bearings, pulleys, or it could be interior in the motor.
Something loose? Exhaust pipe rattling/hitting on something? You'll have search it out.
Check to heat-shield at the catalytic converter because something is loose
Rattling noise is probably just a loose muffler, muffler pipe, or a loose heat shield that is hitting chasey or something else.
There is probably something not bolted correctly and is coming loose
I drive a 96 mustang,and was told that the 1990-2000 model's body is made from sheet metal and on bumps,or a dirt road it will make rattling sounds. Your exhaust pipe is another explanation if it is loose.
Your Mazda Protege might make rattling noises when parked because of a loose or damaged muffler or even body panels that are loose. It might also make a rattling noise because of a damaged motor mount.
It will take some detective work to locate the source of the rattle. Look for something loose or out of place.
A rattle can be caused by any loose part.
usually a loose bolt
That sound is a bad thing. it could be loose hardware.