[Spartarus]

It's almost impossible to burn up a valve in this car. There are so many weaker links in the chain.

DI seals could cause this, as could a failing coil pack, as could a broken and intermittently working cam phaser, or any combination of those.

I can fully explain any of those potential diagnoses if necessary, but a burnt valve does not fit the bill.

The stock exhaust valves are sodium-filled and incredibly heat resistant. If it was an intake valve you would have much bigger problems.

P1235 is interesting. Most of your codes relate to bank 1 cylinders, and you have a VVT issue on bank 1 intake cam. Just saying. That could explain bad vacuum with fine compression but bad running. Say it's stuck or intermittently stuck in the fully retarded position.

Could also explain intermittent afr fluctuation, but not the low fuel rail pressure. That's either a false code or another issue entirely.