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Old 05-24-2013, 09:02 PM   #1
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default 2.5i slightly rich

my AFR is always 14.3-14.5 during cruise. sometimes during deceleration at slow speeds AFR dips to 13s and it wont hit 14.6-14.7 until idling for a minute. My MPG is down at about 20mpg for around town driving (avg speed 30mph no traffic and light throttle use). no codes and car is stock with only 45k miles. any ideas?
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Old 05-28-2013, 10:51 PM   #2
mikeydrives1
Scooby Specialist
 
Member#: 262117
Join Date: Oct 2010
Chapter/Region: Tri-State
Vehicle:
2001 Forester STI
MKtuned

Default

It might be time for a general tuneup. If your front 02 sensor is fouled up, the rest of the engines performance will be affected and run richer than it needs to be. Try doing new plugs, fluids, filters, and if need be, remove the front 02 and check to make sure it isnt caked over or anything.

-Mikey
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Old 05-30-2013, 06:38 PM   #3
Pickler
Scooby Newbie
 
Member#: 301247
Join Date: Nov 2011
Location: Toronto
Vehicle:
09 Impreza 2.5i MT
White

Default

i did all of that except i didnt remove the front o2 sensor. new plugs made 0 difference. since day 1 my cars long fuel trim has been averaging about -7 and during cold starts as low as -15. short trims are ok though.
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Old 05-31-2013, 11:37 AM   #4
Bamofo
Scooby Specialist
 
Member#: 159743
Join Date: Sep 2007
Location: Plymouth Ma
Vehicle:
07 STI Limited
TurboMike Tuned 2.35

Default

Decel is setup to add some fuel when you let off or press on the gas... Target Closed loop also has a huge table... if you PM me your rom i can take a look at it and help with the gas mileage. thats really crappy though. My step mothers outback came getting 25ish on 87... we got it up to 32mpg with some tuning on 93. she runs 91 though so she is getting around 30....

Its doable.
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