So this has happened to me twice and i wanted to see if anyone else had this problem. I have a 09 wrx and the first time i changed the oil i put in a little too much. The car instantly started getting 1-2 less mpg. I checked the dip stick and it was a little high, I drained a little and the car went right back up to where it normally cruises at. Ive done another oil change and was carefull to make sure to get the right amount and everything is great, even with stage one i average 25.7 mpg. I do baby it most of the time. It was time for another oil change and i didnt feel like doing it so i found a local place that would install my oil and my filter for 16 bucks.. seemed good to me, no jacking up my car, getting oil on me and making a mess.. So after they are done i notice there is a little less oil left over than what should be. ON the ride home my mpg drops right away down to between upper 23's to 24.3. mpg from 25.7 So tonight i spent a half hr draining some oil out... I am assuming ill be back at 25.7 mpg tomorrow on my way in. Has anyone else had this issue? It cant be a coincidence. Since having installed the accessport over the course of 1000 miles i managed to average 25.7 and babying my car driving home and less than 20 miles that average dropped more than 1 mpg... Seems to me like our cars are supper sensitive to too much oil, and im not talking a lot extra, instead of 4.2 maybe 4.5. It doesnt take much, atleast for my car to get pissy.... Just curious if im the only one or is everyone putting in too much and just getting crappy mpg??