Got my first check engine light today. Just recently did a sea foam treatment and had switched over to mobile 1 synthetic. Since switching over oil consumption had gone way down from 1 quart every 500 miles to less than 1/2 a quart if that even, though it would seem to be fine for a long time and then all of a sudden boom just gone. Not changing driving habbits or ramming on the throttle. Will take in today to get the codes pulled I think it's just an o2 sensor. The engine seems to be running perfectly fine. Had just added the cold air intake as well was wondering if it may be part of the reason as also. Guess I just have to wait till I get the codes. Whats peoples opinions on oil between mobile 1 synthetic and the rotella 15w40. I used to use heavier weight oil in my gen 3 rx-7 because it helped with the compression issues on the stupid rotary but why such a heavy weight oil for the vx. Noticed alot of people used was just wondering if kind of for the same reason.