It is alright to have worldly possession, because you are on this Earth surrounded by them. But to dwell into dwell like an idol is a sin.
The question is how much do you devout your time and self to Jesus?
How much do you love him with all your heart, mind and soul?
If you are collecting lots of car materials, which is not good for Jesus gave a parable of a man who keeps worldly possessions. He torn down his barn to keep collecting more. How terrible when he looses his life, all that will go to a waste. But we should think of heavenly things above.
I have my worldly passions which is games. Before I was born again, i would dwell in them so much just going into gaming news and learning so much. But now I'm Born Again, there's time for God and time for games. It's because my potential is under games and I wish to become a game designer and work in the gaming industry.
God does not give us world passion but skills and talent. So your passion is cars which God gave to you. For people who wants to live their potential and what they can do, God gave it to them. That is why people are so good at what they do: doctors, physicians, mechanics, actors etc. They had that potential from young and eventually followed it into their career.
Not everyone needs to be a pastor or do work in ministry.
I would just suggest you fast to the Lord and cut off all communication with the world and cars. Fast in reading the bible and prayer to the world. I would suggest 7 days but I recommend 3 days. You need to prove to God, devil, world, spiritual realm that your love is for Christ, yet you have a passion for cars but it will not be your idol.
What you need to do or trying to do is to control your time with cars and more time with Jesus.
//god bless