There are a lot of threads like this so just do a search, you will find a lot of useful information. Sounds like your ideas come from passion which as MJ talked about in his books, aren't always the best route. There are a ton, as seen on here if you search, people who like cars and gaming. Some of the new people have tried building sites around those ideas and fail. Not saying you can't be successful, but you need to find a need to deal with if you want to make money. Don't just make a car or video game website for the sake to make it because you like it.
I did the same thing when I started, now I look back and can't believe I was that stupid and selfish. My current project I figured out a few months ago and has a specific need that I will solve, can be scaled, has barriers to entry, and more that I am drawing a blank since its late. lol.
Not sure if you read MJ's book yet but if you haven't, I would suggest doing that. Best of luck!