'09 Premium getting horrible mileage... need help!
I purchased the Forester new three years ago, and have made several modifications to it in order to improve fuel economy. Below is the list as of current:
Lowered 4.5" inches on STI coilovers
Tires at 43-45 psi
Roof rack removed
Straight exhaust (no cats/no muffler)... this gets swapped back and forth with the stock exhaust as it gets too annoying.
Some parts removed/lightened.
Average mileage over the first 77,000 miles was 27.6... the last year or so it has been closer to 30. If I really watch my foot and hyper mile I can get 36-37. Rarely is it under 26, ever...
Last month the oil pump seized and the motor failed. I replaced the motor with a new OEM motor.
Upon start up there was a bad fuel leak in one injector... mileage was around 18-20. Made sense considering the gas was spraying out like a squirtgun. I drove it for a total of 55 miles before I parked it and waited for the O-ring (week wait from the dealership).
I replaced the O-ring and the leak was fixed. However the mileage is still terrible...The other day is was 12-15 mpg around town. The best I would see was 19-20 on the higway at 65. Its been about 250 miles and no improvement.
I do have an engine light on, however this has been on since nearly day one when I switched exahausts. This has never had any ill-effect on mileage previously.
I've read that a bad O2 sensor can cause horrible drops in mileage, but this bad? I'm having my codes checked tonight and I'll go from there, but wanted to get some opinions/feedback as well. I ordered a new O2 sensor (both) but they sent the wrong parts, so its another week of driving this way....
Any have any ideas??
Thanks in advance!