https://youtu.be/_Uu6Vb9unDo
Here is a video of the car running, let me know what you guys figure, ask any questions and ill try and answer as much as i know from what the previous owner has told me.

Simple explanation, the car has a hard start, takes some effort to start it, when running it wont stay idling, i have to give it a little throttle to keep it between 3 and 4k rpm.. after it hits 5k it wants to bog and die a bit but seems to quit after about 6k but too scared to really try.. once i let off the throttle it dies after dropping below 1k rpm but at one point it did try to hold on and bounced from like 500 to 800 rpm before dying shortly after.. havent done a compression test, mazda is pretty booked but have an appointment in a week. Give me whatever opinions you need!

 

That flashing check engine light might be a clue. What code is it throwing?
Flashing check-engine = misfire. Backfire = fuel in the exhaust = misfire.

I sounds ignition-related, so coils, spark plugs, etc. If you haven't changed them, do that. Check your catalytic converter (like remove it and look inside as much as you can). If any of those things are broken, they need to be fixed.

Also don't rev the car cold like that.

 

My bad on the revving cold, it had been running for a few minutes already, and im not even sure if there is a cat on it anymore i think the previous owner said he straight piped it but ill double check. Ignition coils is what im hoping it is because i dont want to spend a ton on replacing seals or potentially a different engine.. but if it needs to come to that then ok, Im just wanting to have it running by summer.

 

The guy said it has a cat still, in his words "the muffler was just tubed"

 

If replacing seals = Rebuilding engine.

 

I would try to help you, but you filmed in portrait, which is irredeemable. Probably best to set the car on fire and walk away.

(You might also read the misfire thread and start going through the troubleshooting steps. A blinking CEL is always a misfire.)