Error Code PO456 and something else
 

Hello!

I have a 2005 Mazda 3 Hatchback with around 115k miles. I have replaced the thermostat in the past around 106k miles.

It threw code PO456 as the title says. Did a bit of research, could be gas cap so yesterday i reset cpu and code is gone (for now will update haven't driven much since then).

On top of that though, the car shudders? or makes that kind of noise upon startup this happened twice in the past two weeks. It does go away after a few minutes

After reset, now the car has died while I was sitting in first waiting to go, then almost died again as i down shifted into 2nd from 3rd.

Maybe clutch is on its way out?

I do regular oil changes with full synthetic oil

light still has yet to come back on. A/C went out, car runs fine now i guess it was the ac compressor killing the engine at idle.

In that video he shows how to replace an ac compressor. Do I have to use one specifically for a mazda 3 (such as ) or can i use a more generic version?

You need a compressor designed for the car.