('09-'13) '09 Premium getting horrible mileage... need help! - Subaru Forester Owners Forum
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post #1 of 1 (permalink) Old 07-09-2012, 11:40 AM Thread Starter
Forum Member
Join Date: Nov 2011
Location: Menasha, WI
Posts: 9
Car Year: '09
Car Model: Forester
Transmission: 5 speed
Feedback Score: 0 reviews
'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
Custom intake
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!

SENZA PARI is offline  
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