[bc.]

Stop talking about engineering, he already said he is bad at math so that is out of the question.

OP, I would not recommend doing Tech school, if you are gonna work on your own car anyway, you don't need to do it everyday for somebody else. If working on cars is the only thing that makes you happy, then maybe forget what I said. Biz school is great and not very difficult or math intensive and will be a more solid starting platform for career development than Tech school.