what is this fallacy called? For example, that car has 4 wheels, therefore it must be a ferrari.

Yes, that could work. I just thought there would something more formal to describe the insufficient conditions met besides "jumping to conclusions."

The car with four wheels is just a simple example, not quite a 'false equivalence' type of situation. I'll try to come up with a better example that's more specific. Should I start a new question for that or continue on this thread?

This thread is fine. If you present a formal argument (deductive argument), we can look for a formal fallacy. Right now, informal fallacies would be just fine to describe this (and accurate).

I don't think that's the one. Mine would be more like if p, then q. Therefore Q.

if a car has four wheels, then it must be a ferrari. Therefore it's a ferrari.

affirming the consequent has "therefore P".

Logical Form:

If P then Q.

Q.

Therefore, P.,

Yes, I think that can apply. But non sequitor seems to be a broader class, and mine is a little bit more specific. The ferrari does have 4 wheels, so in that sense not as absurd as typical examples for non-sequitor.