I mentioned this in the first impressions thread but bound to be overlooked there.

In the 60's cars I get this thumping sound, like someone is banging on the hood of the car, or something keeps knocking on the road. When I accelerate the sound disappears but it's there pretty consistently otherwise.

It doesn't sound like a bug but maybe the simulation of a certain noise, in any case it's extremely annoying/distracting so wondering what it is and if it is meant to be there?
Ideally I want to get rid of it!