Thanks for the post. I am assuming that you are yet to consult with one of our career experts on the platform. If you haven't done so yet, I would suggest you to do that as soon as you can so that you get more of an in depth perspective on possible/ alternative options.
Here is the link- https://yourdost.com/talkItOut
From what you have shared, as an engineer you have a deeper understanding of how cars work, their pros and cons etc.
Since most car salesmen are purely from a sales/marketing background, they overly depend on their selling skills rather than having a true understanding how things work. You can prove to be an asset in filling this void by being the go to person for FAQ's regarding technical specs and providing objective judgments. However, if you still want to thrive in this field, you need to focus on improving your social skills to an acceptable level so that clients find you interesting as well as knowledgeable. This can be done over time if you put your mind into it. Also, you can find your own unique flavour and take on sales pitches and hone it rather than rehashing old punchlines. The point is, it is not necessary to sound and act like any other sales person.
Since you are unemployed at the moment, you can give this a shot and see it as a learning curve with an earning opportunity. If it works out pretty decent, then you can be satisfied knowing you can handle cross over roles, and comfortable at challenging yourself.
All the best!