P0028 SUBARU - would the type of oil i use effect the sensor, i use castrol gtx full syn 5w-30

Question

also i use an K&N oil filter and air filter with only 58k miles

Answer 1

Yes, and 0W-30 is what the factory recommends. How often do you change the oil? If you change the oil regularly and is clean, then you may just have a defective valve.