1. Maybe after the first test, you stopped treating your practice exams seriously, and you got little bit ballsy (it happens to me).
2. Reading passages quickly is not the key to succeed in CARS. Anyone can finish reading MCAT passages in 3-4 minutes with practice.
3. From what I understand from your post, you don't emphasize reviewing your CARS questions and why you answered incorrectly. This is really important thing to do.
Check out test solution guide. I'm trying it right now and it helped me a lot.