Keep this in mind:

Quality of life is not the same thing as standard of living. What I mean there is that just because a job makes good money, doesn't always mean you will be happy. Doing a job that you enjoy brings quality of life, money improves standard of living. If you can have both, great, but I would much prefer quality of life (i.e. a job you enjoy).

Hobbies and interests are usually a great place to start. There is money in the automotive industry... but its a rare few who get rich from it.

If you really want to do car stuff, consider a path in mechanical engineering or automotive design. There are specialty schools out there for that sort of stuff. If you have the brains and talent to really do great things in the automotive field, get out there and be the best you can be.

If you are anti-school and just want to work on things, I guess a mechanic job would be ok but hardly aspirational. Maybe working for a race or specialty shop would be really cool tho. I don't know what the market is like. NASCAR mechanics all have engineering degrees...

Still having trouble deciding what you want to do? Find a career counselor. Take one of those aptitude tests that determine your strengths and suggest possible career opportunities. Read some career decision books (i.e. what color is my parachute)

What other hobbies or interests do you have?