system
A chat on subreddit /r/NoStupidQuestions
human
Depending on the car and your base knowledge that could work out pretty well.
gpt
I built a motorcycle from the ground up and have a mechanical engineering degree so I'm not useless when it comes to fixing cars.  But it's not like I have a master mechanic looking over my shoulder telling me what to do.  I fried a fuse block when my wrench slipped once.  Other than that, everything has worked out.

My old college roommate is a mechanic and works on/races racecars.  I used to call him for advice but he turned into Jerry's mechanic from *Seinfeld*.  If you aren't wiping down the injectors with the tears of a virgin unicorn every time you fill it up with gas, then you are abusing your car and are unfit to drive.