Rattling/scraping sound mazda3 2004
 

Hello,

I just made an account because I have taken my car to four mechanics so far an every one of them tells me it could be something different.

https://www.dropbox.com/s/by2gfbov1mcy2ba/Car%202.m4a?dl=0

the sound starts 15 seconds in. It's almost like the engine is stuttering? I'm not sure how to describe the sound. It's like the clear engine sound is being interrupted.
It makes this sounds in all gears (it's a manual). When it's out of gear it sounds fine
I've replaced the tires, struts/shocks, brake pads on front, thermostat, coolant container(it was cracked).
I bought this car used. Previous owner had hit a curb with right side of car and the tire had gotten up in the wheel well.
Also the Compressor is broken, I had it checked and was told it burned.

So grateful for any advice on this car. Thank you.