Originally Posted by zip159

I went in to the dealer last weekend for my 2nd oil change and this time I got Mobil 1 Synthetic Oil instead of the standard oil that they offer (not sure what it is). After getting the oil changed I've noticed that I haven't been getting nearly as good of a MPG average.

I'm 400 miles into the first synthetic oil used in the car so maybe that has something to do with it?

Anyone experienced something similar whether it's changing the type of oil or increase A/C usage?