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Old 05-11-2015, 12:59 PM   #1
vincent-h
Scooby Specialist
 
Member#: 59504
Join Date: Apr 2004
Location: Chestermere/Calgary AB
Vehicle:
2005 Impreza RS

Default Engine stuttering/ running rich? 2005 2.5 RS

Been having troubles with my 2005 Subaru 2.5RS as of late and can't figure out the exact problem.

Symptoms:
Can is stuttering and seems to be running overly rich based on my wideband (7-11 AFR). Cannot get any acceleration out of it and it's just really chugging to move. With the MAF unplugged it runs near flawlessly.
No CEL code is currently coming up when the MAF is plugged in and the symptoms were occurring.

Repairs to try to fix already completed:
- Battery pulled and ECU reset
- Cleaned old MAF, then completely replaced it instead.
- Replace Front o2 Sensor
- Replaced Rear o2 Sensor
- Replaced All Spark Plugs

Notable Mods:
- Full headers back with no cats
- Injen intake
- Street Cams

Current Ideas:
- just needs a tune? (It has been tuned in the past for all mods using RomRaider prior to all sensor/MAF changes)


Any other help so I don't have to keep driving with the MAF unplugged. Willing to try anything within reason but as the car is getting old anything reaching half the cars value will likely lead to the car being taken apart and parted out. I'd still rather keep my scooby running as it seems to be running fine with MAF unplugged!

Cheers and all your help is greatly appreciated!
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Old 05-11-2015, 07:25 PM   #2
yarrgh
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Member#: 80465
Join Date: Jan 2005
Chapter/Region: RMIC
Location: Aurora, CO
Vehicle:
2001 2.5RS
Black Diamond Pearl

Default

Check the wiring to the MAF. unplug/clean all connections from there to the ECU.
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Old 05-17-2015, 02:22 PM   #3
weezer88
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Member#: 357352
Join Date: May 2013
Chapter/Region: MWSOC
Location: Michigan
Vehicle:
1999 Forester

Default

any update on this?
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Old 06-15-2015, 02:32 PM   #4
vincent-h
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Member#: 59504
Join Date: Apr 2004
Location: Chestermere/Calgary AB
Vehicle:
2005 Impreza RS

Default

Issue is still occuring. I realized the rear o2 sensor needed to have it's wires extended I'mt wondering if those extension wires are shot, so will try to buy new wires to extend the rare o2 sensor.

Anyway to test that and instead of unplugging the MAF would there be any affect in unplugging only the rear o2 to test it?
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Old 06-15-2015, 08:08 PM   #5
weezer88
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Member#: 357352
Join Date: May 2013
Chapter/Region: MWSOC
Location: Michigan
Vehicle:
1999 Forester

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Friend of mine has had his rear o2 sensor unplugged forever. (actually the wires are cut and dangling haha). his car drives great.
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Old 06-15-2015, 10:26 PM   #6
kos
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Member#: 118334
Join Date: Jun 2006
Chapter/Region: SWIC
Location: Bouncing off Kerbs
Vehicle:
2005 AW RS + 2006
Time Attack WRX

Default

Vacuum leak post-MAF?
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Old 06-16-2015, 10:43 AM   #7
vincent-h
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Member#: 59504
Join Date: Apr 2004
Location: Chestermere/Calgary AB
Vehicle:
2005 Impreza RS

Default

Quote:
Originally Posted by weezer88 View Post
Friend of mine has had his rear o2 sensor unplugged forever. (actually the wires are cut and dangling haha). his car drives great.
that's good to know the p0420 has been cleared from the ecu through a tune a long time ago as well.
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Old 06-16-2015, 07:55 PM   #8
wtdash
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Member#: 59182
Join Date: Apr 2004
Location: N. Idaho
Vehicle:
2002 WRX GG>>
2016 Focus RS

Default

Older, as in '90s models, ran Rich when the CTS was bad - even though no codes. Look there, too.
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Old 06-21-2015, 12:30 PM   #9
klaus_b2
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Member#: 318411
Join Date: Apr 2012
Chapter/Region: South East
Location: North Carolina
Default

there was a whole thread on this somewhere, but i can't seem to find. it listed all of the reasons and where to start. its very common with the ej motors. but have you tried the pcv valve? mine started doing the same thing, i changed plugs and wires, pulled a little bit harder, then one i replaced the pcv valve it was running like a champ. plus it was only a $20 fix. might not fix your problem but won't hurt to try
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