A little back note first. I just replaced my A/C compressor last week. I also found out I have a small leak in the bottom of my oil pan from hitting a pot hole. I went to the oil change location and then filled my Passat 1.8T 2002 with 10w40 Castrol Synthetic oil since it was low. Well since they did that I have noticed the engine light has been coming on intermittitly since that giving me P0012 AND POO10 codes. I even drove the car on the highway for 80 miles on Saturday with no light but then it came back on again. No strange sounds, etc. Could it be the new oil? I replaced the CCT 2 years ago and it has been quiet and fine since. I also did the timing belt then. Any help would be great Thanks