Can you clarify what you mean by “instantaneous resurgences”? Did something happen that made you get really high grades after not such great grades? Is it something that a guidance counselor should address in the letter of recommendation?
If your school offers AP classes, colleges are most impressed by high grades in those classes. Self studied APs don’t count for much and can be frowned upon if it seems that the student is just trying to impress. If you want to take AP exams for credit or placement, go for it. But don’t expect it to make up for low grades.
On the other hand, if your school offers very few APs, and the subject is interesting to you, there’s no real harm in self studying IF it doesn’t interfere with your grades and other activities. Just don’t expect a big payoff if you try to self study for a lot of them.