I drive a 2011 MR with about 10K miles on it so far. I drive about 20-25 miles a day and fill up on premium (93) from Sunoco all the time. I get a consistent 16-18MPG in pure city driving. When I do highway I can get up to 24 when I grandma it.

The last oil change I did I put 5w30 quaker state full synthetic and I'm ready to do my next change (3k miles). To me it sounds like you may have a deeper issue than the oil. I live in PA and I've always been able to hit the "normal" average MPG no matter the temp, so I would agree with the others that you can discount the temp theory.

 

agreed. at least a few mpg drop every year at this time

 

sorry for the late late responses guy...

PROBLEM SOLVED.

my dumb a** put too much oil in the car... MPG Fixed.

End of Post.

 

sorry for double post but +1 for colder weather being the cause. i was soo used to miami gas for soo many years, after taking the car back down south MPG went back up even higher than normal.

cold start's + extra oil + bad cold weather gas = 13 MPG

 

just jumping in real quick: assuming someone already asked how long you let the car warm up in the morning. idling is 0mpg.

plus, i think the colder the coolant temp, the more fuel is added?