all these codes lit up today while on a short drive:

p0174, p0300, p0304, p0303, p0305, p0307, p0171, p0134

Couldn't find thread naming all these codes to come on at once. I know what they mean individually, but not all of them at once?

Where do I start troubleshooting?

 

As you know, 4 of them are misfires. I'd start there. The others are probably related, if you had none to start with.

Start really simple. Fuel, air, spark.

So, do you still have fuel pressure? Read up how to get to the little valve, convince yourself there is some go-juice reaching the right place.

Check the MAF connections, MAF in general for signs of something up with it. That there isn't a dead animal stuffed in the intake (I found a mouse + massive nest once).

Indicates 4 cylinders on different coils, but I'd have a feel at the coils. Check it all seems good. Engine hasn't got a massive soaking recently, washed it etc? Wires decent condition?

Check battery voltage and connections, as low V or bad ground can throw multiple codes.

I assume it runs like a dog with 4 cylinders misbehaving. If it doesnt run like a dog, then that points you somewhere else completely.



That's where I'd start. Others will have specific things I'm sure.

Oh, if they are genuine misfires, don't run the car for long. You are piling unburnt fuel into the cats, this then burns in the cats and melts them.

 

Looks like you're lean on both banks. Which is probably giving you all the misfire codes. The P0134 is a no activity O2 sensor code, which could possibly be caused by low fuel pressure in some cases.
I would do a fuel pressure check to start with. Then go from there.