Melted valves... Two valve heads were sitting on top of the piston melted and disfigured.. These were Supertech valves as well. Motor is an EJ207 with EJ20K heads.

I am pretty sure my o2 is on its way out, reads 0.06v when cold and 0.00v when driving some times..

Anyways... I was trying to diagnose a misfire at 2500~300 and yeah i was planning to buy an o2 sensor that weekend and this just happened...pics tell the story I guess. i am heart broken.

It was appox 2500~3000rpm, light throttle, cruising..2nd or 3rd gear.

Would others agree a faulty o2 sensor the most likely cause? The car is tuned using powerfc.

This thread had the exact same thing happen!

Car died and will not turn on. - Page 3 - Subaru Impreza WRX STI Forums: IWSTI.com

I need some expert feedback