The rattle appears as I rev the engine at a certain RPM. It happens in every gear. I had the car jacked up and the heat shields checked today when I had my tires rotated. Unfortunately for me my 2006 Toyota Corolla was NOT doing this when I was at the tire shop. I opened the hood and the sound is NOT coming from the engine. It sounds like it is coming from the middle of the car, or maybe the passenger side. I am stumped. I did all the maintenance on the car and everything.
I can only tell where my similarly placed “rattle” is coming from…a broken weld in a exhaust heat shield which you say you have not discovered. Otherwise, I have had them in the past eminate from an exhaust pipe that either by hitting something or age of the hangers, found themselves too close to a frame member or other component or structure. Often, it can be illicited by just shaking it by hand from underneath but ometimes not. I would check clearances and look for damage allong entire length of exhaust. These are guesses from some one who just turns the radio up as his cars age.
Here is a possible wrinkle to the story. About 3 and a half years I was in a low speed front end collision with this car. I had the work done by a reputable shop 5000 dollars worth. Is it possible that a wield popped loose and that is the source of what I am hearing?
Anything is possible.
When you took it to the shop, did you ask them to “check the heat shield” or to “find the rattle”? I only ask because this is a common error people make. They suspect some particular thing and only ask the shop to look at that particular thing rather than to look for the cause of the problem.
I had a rock in the heat shield rattling once. It could be a broken weld or even a internal rattle in muffler or catalytic converter.