Miata Update -
Here's a second blog post in one day! I don't know if I want to actually punctuate these better so they're easier to read or not. I think I'll try it with this one. I was messing with my Miata again today. It was running fine. I switched my old coil pack back in to see if it would start. It did. I drove around and it drove just as good as the new coil pack. I left it in and went to the gym.
Lo and behold, it didn't start when I tried to leave. Thankfully my girlfriend was there and she helped me get home. I grabbed the old coil pack, a 12mm wratcheting wrench, some 90 degree pliers and I proceeded to switched to the new coil pack in as quickly as possible (I've done this like five times now so I'm basically a pro). It wouldn't start even with the new coil pack. RETURNING THAT!!!! ILL TAKE MY 200 BUCKS BACK THANK YOU VERY MUCH!!!
Swapped the old one back in and it fired up. My assumption here is my catalytic converter is shot. I bet the exhaust gasses are choking the engine out so it starts for a little sec then immediately dies. Once I let it sit for a while-- siwtching the coil pack twice-- the exhaust gasses left the cat and I was able to start the car again.
When I drive like a grandma, such as to the gym or to Smith's, that's when it doens't like to start back up. When I drive like a maniac on the freeway for 20 minutes to see if the car will die on me, it's fine. One of these driving styles heats up the catalytic converter way more and probably pushes a lot more exhaust via pressure.
Like I said in my first Miata post, I'm not a professional mechanic. I don't really know what I'm talking about or doing. I'm really just pulling this knowledge from nothing, so don't take this blog post as advice if you have the same issue. I'll post another update if I buy a new catalytic converter and I'll let you know if it fixes the problem or not.