Fluctuating ACT Score

I took the ACT twice, the first in September and the second in October. My composite score was a 33 on the 1st and a 32 on the second. However, what I'm most worried about and debating is my subscores.

For the math section, I got a 31 in the 1st and a 33 on the second. However, I got a 33 on the reading in first test and a 28 on the second test, which is a significant drop.

Is it recommended to send both test scores, even if the school super scores the ACT? I'm planning to pursue an engineering degree.

I would recommend sending both scores, particularly for schools that superscore. If you're applying to engineering schools, you definitely want them to consider your highest Math score, which is your score from the first test.

However, you're correct that a 28 on Reading is significantly lower than the 33 you got on the first test. Add this to the fact that some schools consider your highest ACT score from a single instance of the test, rather than highest individual section scores, and you'll want to have your first test score (with your 33 composite and 33 on Reading) considered as well. The only reason not to send both scores is if it would be a financial hardship.