Check that the turbo is spinning freely. Just went thru the same sort of problem with a turbo diesel loader at work. It was fine one week, and started eating fuel and smoking the next. Journal bearings went south and it bound up, restricting/limiting air flow and causing a rich mixture.

With EFI and an O2, it might not be the cause, but ya never know.

I want to die like my Grampa, peacefully, in his sleep. Not screaming in terror like his passengers.