About a year ago I had the valve cover gasket replaced, a new air filter, and the throttle body cleaned. As I pulled out of the shop's parking lot, I noticed a vibration by the accelerator and unusually loud engine noise when I accelerated. I immediately took the vehicle back to the mechanic, but he could find no reason for the change. I saw an article about cars that had a tube in the engine compartment that plugged into the exhaust pipe, before the catalytic converter, which sometimes broke or rusted off. Could this possibly be the cause of the excess noise? How would I have this diagnosed (if that is the source of the noise)?
Abnormally loud when accelerating on 1997 Toyota Camry
Unfortunately there is no answer that can be accurate until the vehicle is inspected and diagnosed to the root cause. If the problem happened immediately after service, as a professional automotive technician, I would look where I was working last and check that out. Since it's been a year that may be difficult.