Million dollar app idea. Shazam, but for that weird sound your car is making.

Tweet by Aaron Mitchell (@aamitchell)
I think this can be made. The app should identify car model and position of the phone. The user can enter this. And based on the noise, very minor things can be noticed. It can work with a large set of users, but it's hard to maintain accuracy and retention.
Must be so hard to recognized :o
This exists. I forgot the name of the startup but it is from Eastern Europe and they are licensing the tech to big name car and airplane brands.
My vote goes for the engine car sounds identifier
Already being done. https://www.smithsonianmag.com/innovation/app-can-diagnose-your-car-trouble-180967412/