Gas breaks $4 mark at a North Side gas station.
Fill up your tank because gas is going up.
At least one Chicago gas station broke the $4 mark Wednesday.
A gallon of mid-grade unleaded gas inched up to $4.02 at the Citgo gas station at 5300 N. Western Ave.
Regular unleaded at that station was only 11-cents from the big $4.
AAA is reporting the average price of a gallon of unleaded gas is $3.86 in the Chicago area.