Q: Car shuts off or shakes

Hello. If this issue is only occurring when you are at a stop and drives fine at higher speeds then it is typically caused by a vacuum leak. This can be caused by a gasket failure or a vacuum hose that are old and need to be replaced. With the engine running. A mechanic would start by checking for hoses that are cracked or loose and making a hissing noise. This is an indication of a vacuum leak. If nothing is found then it may have an intake gasket that is leaking or even a sensor problem. At that point the mechanic would check the sensor outputs and even do a smoke test to try and find any additional leaks.