My opinion towards flirting. It's not alot of fun, at best it's a little bit of fun. From what I have seemed to notice in general, most girls seem to get way more fun/enjoyment out of flirting then I do/men do.
I only like flirting very much, when I do know it will (almost certainly) lead to sex. Flriting without sex, for me isn't satisfying at all.
Therefore I in general, try to do some "testing" when a girl is flirting with me, if she is for real. Those tests are in general things like: standing/sitting close for a moment (does she pull back or not?); stroking her arm or hand (does she pull back or start participating), and stuff like that.
The above I'll usually "try" twice if necesairy. If she participates and/or doesn't pull back, she is usually for real and I feel I can relax about it (leading to sex). If she pulls back twice and/or doesn't partcipate at all (yet does flirt), I'll usually conclude she isn't for real and stop participating in her flirting. The above are not really set rules, since for me my gut feeling plays a role in the decision also.

To add. Flirting is imo, often more about ego boosts then about getting it on. It's more about affirming (for girls) that they can/could attract someone or get attention from someone, while for guys it's often more about getting affirmed and being able to show/tell others (buddies) that they have a hot/cute girl that finds him attractive/cool /interesting. Since I've noticed guys only brag about hot girls flirting with them, yet never about an ugly girl flirting with them. So if guys really find the act of flirting so enjoyable, they would like to do that fun activity as well with ugly/fat girls, I would assume?
To ask. Beyond vibe, was there more coming from her? Or did you test for? Did you or she try to initiate anything (remotely) physical?

A vibe was there that this girl is ready to go out to my car and fuck right now, then as soon as I started throwing back this vibe

Yes, that's it. Come on an internet forum and make it sound cool.