Welcome to the North American Subaru Impreza Owners Club Friday December 19, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Factory 2.0L Turbo Powertrain (EJ Series Factory 2.0L Turbo)

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 03-07-2013, 12:44 PM   #1
CryderSpeed
Scooby Specialist
 
Member#: 88816
Join Date: Jun 2005
Chapter/Region: NWIC
Location: GET BACK
Vehicle:
TO TWERK

Default Suddenly Getting TERRIBLE Gas Mileage!

Hey all, apologies if this ends up not being in the right subforum but it's a place to start.

I've got an '05 Saabaru with 116k on the clock and the car has been essentially trouble free apart from replacing the A/C system last summer. I typically average 250-260 miles a tank during mostly urban driving but over the past week my mileage has been cut by more almost half.

Car still drives fine, no loss of power that I can feel, no CEL's, no weird noises/vibrations. Tires are properly inflated, oil is freshly changed, tmiing belt done at 100k, etc. Car has Cobb Stg 1 flash and a Perrin air filter but powertrain is otherwise stock.

I'm planning on taking it in to my mechanic but I'd like to have an idea of what's going on, anyone got any ideas? Thanks in advance!
* Registered users of the site do not see these ads.
CryderSpeed is offline   Reply With Quote
Old 03-07-2013, 12:51 PM   #2
imprezats032
Scooby Specialist
 
Member#: 306200
Join Date: Jan 2012
Chapter/Region: NESIC
Location: western mass.
Vehicle:
2002 wrx sedan
wrb

Default

Is the air filter clean? How about the fuel filer?
imprezats032 is offline   Reply With Quote
Old 03-07-2013, 01:17 PM   #3
CryderSpeed
Scooby Specialist
 
Member#: 88816
Join Date: Jun 2005
Chapter/Region: NWIC
Location: GET BACK
Vehicle:
TO TWERK

Default

Quote:
Originally Posted by imprezats032 View Post
Is the air filter clean? How about the fuel filer?
Air filter could probably use a scrubbing but typically stays pretty clean during the winter on account of all the rain here. Never messed with the fuel filter, since my car is a 2005 vs 2006 the FF should be under the hood on the passenger side, correct?
CryderSpeed is offline   Reply With Quote
Old 03-07-2013, 01:37 PM   #4
jh57
Scooby Newbie
 
Member#: 314962
Join Date: Mar 2012
Chapter/Region: MWSOC
Location: NE Ohio
Vehicle:
2003 WRX Wagon
Silver/Black

Default

Might have a frozen or sticky brake caliper. Go for a normal highway drive then feel the lugnuts on each wheel for an unusual amount of heat.

Wife's Honda Element just did this in Jan. Her MPG dropped about 20% suddenly. I cleaned and greased the caliper pins and her MPG went back to normal instantly.
jh57 is offline   Reply With Quote
Old 03-07-2013, 01:43 PM   #5
KOJAK-02-WRX
Scooby Specialist
 
Member#: 208052
Join Date: Apr 2009
Chapter/Region: MWSOC
Location: Southern Indiana
Vehicle:
2004 SGM FXT-6speed
*SOLD* 02 PSM WRX

Default

Try cleaning MAF sensor could help or O2 sensor could still be bad without code.
KOJAK-02-WRX is offline   Reply With Quote
Old 03-07-2013, 01:46 PM   #6
CryderSpeed
Scooby Specialist
 
Member#: 88816
Join Date: Jun 2005
Chapter/Region: NWIC
Location: GET BACK
Vehicle:
TO TWERK

Default

Quote:
Originally Posted by jh57 View Post
Might have a frozen or sticky brake caliper. Go for a normal highway drive then feel the lugnuts on each wheel for an unusual amount of heat.

Wife's Honda Element just did this in Jan. Her MPG dropped about 20% suddenly. I cleaned and greased the caliper pins and her MPG went back to normal instantly.
Interesting, I did just have a full brake job, will investigate, thanks!
CryderSpeed is offline   Reply With Quote
Old 03-07-2013, 02:14 PM   #7
Cory51191
Scooby Newbie
 
Member#: 332781
Join Date: Sep 2012
Chapter/Region: NESIC
Location: Worcester county
Vehicle:
2006 STI
OBP

Default

First thing I would check is my parking spot/under the car to look for a fuel leak.
Cory51191 is offline   Reply With Quote
Old 03-07-2013, 06:24 PM   #8
Barnt
Scooby Newbie
 
Member#: 161824
Join Date: Oct 2007
Chapter/Region: MWSOC
Location: Caledonia(Racine), Wisconsin
Vehicle:
2015 WRBP WRX
Cobb Stg 1

Default

Quote:
Originally Posted by CryderSpeed View Post
Air filter could probably use a scrubbing but typically stays pretty clean during the winter on account of all the rain here. Never messed with the fuel filter, since my car is a 2005 vs 2006 the FF should be under the hood on the passenger side, correct?
Fuel filter is inside the tank I believe
Barnt is offline   Reply With Quote
Old 03-07-2013, 08:14 PM   #9
bluemk3
Scooby Specialist
 
Member#: 263694
Join Date: Nov 2010
Location: hollidaysburg, pa (central Pa)
Vehicle:
2002 WRX
World Rally Blue

Default

Quote:
Originally Posted by Barnt View Post

Fuel filter is inside the tank I believe
No.. it's not...
bluemk3 is offline   Reply With Quote
Old 03-07-2013, 08:49 PM   #10
greenplates
Scooby Specialist
 
Member#: 239162
Join Date: Feb 2010
Chapter/Region: NESIC
Default

I am a big fan of maintenance. Every few months, I get a bug in my a** and start replacing old parts. It feels good


Perhaps you should do the same.


Here are a few to consider-

o2 sensors (front/rear)
MAF sensor
PCV valve
air filter
fuel filter
brake pads
lucas oil injector cleaner


money well spent
greenplates is offline   Reply With Quote
Old 03-07-2013, 08:53 PM   #11
DZXN
Scooby Newbie
 
Member#: 306186
Join Date: Jan 2012
Chapter/Region: SCIC
Location: Costa Mesa
Vehicle:
2002 Subaru WRX
PSM

Default

Actually I think 05 was when fuel filter went in the tank on the wrx and sti. Not positive.
DZXN is offline   Reply With Quote
Old 03-07-2013, 08:58 PM   #12
kevin85193
Scooby Specialist
 
Member#: 145900
Join Date: Apr 2007
Chapter/Region: Tri-State
Location: east brunswick, nj
Vehicle:
2003 16g wagon sold
05 SWP LGT

Default

Quote:
Originally Posted by DZXN View Post
Actually I think 05 was when fuel filter went in the tank on the wrx and sti. Not positive.
started in 04. BUT some 04's have the FF in the engine bay
kevin85193 is offline   Reply With Quote
Old 03-07-2013, 09:25 PM   #13
Nicklz
Scooby Specialist
 
Member#: 94096
Join Date: Aug 2005
Chapter/Region: MAIC
Location: WV
Vehicle:
2003 WRX
WRB

Default

fwiw I've never gotten an o2 failure code and I've got over 250k miles on my 03wrx.

Every time my o2 started to go out, my mileage will take a huge hit like that.
New sensor and back to 300+ miles a tank.
Nicklz is offline   Reply With Quote
Old 03-08-2013, 09:43 AM   #14
cmiovino
Scooby Guru
 
Member#: 134005
Join Date: Dec 2006
Chapter/Region: MAIC
Location: Pittsburgh, PA
Vehicle:
2004 WRX Premium
PSM

Default

Quote:
Originally Posted by Nicklz View Post
fwiw I've never gotten an o2 failure code and I've got over 250k miles on my 03wrx.

Every time my o2 started to go out, my mileage will take a huge hit like that.
New sensor and back to 300+ miles a tank.
I've had the same happen too... if you keep up with the regular MPG stuff.. aka, tires pumped up, fuel filter, spark plugs, etc on a normal schedule.. normally MPG drops are O2 sensor related. If you haven't changed the front one in a while, I suggest changing it as preventive maintenance.

You may also want to clean your MAF. O2 sensors can't be cleaned, but MAFs generally can. This is good because MAFs are more $$$. Front O2's are about $100-150.
cmiovino is offline   Reply With Quote
Old 03-10-2013, 11:14 AM   #15
D-Rodman
Scooby Specialist
 
Member#: 110078
Join Date: Mar 2006
Chapter/Region: Tri-State
Location: Long Island N.Y.
Vehicle:
05 saabaru artc gr
02 wrx wag wrb ej207

Default

Change the pcv valve, my fuel economy was also hurting and a new pcv valve restored it.
D-Rodman is offline   Reply With Quote
Old 03-10-2013, 04:56 PM   #16
danger1138
Scooby Specialist
 
Member#: 279525
Join Date: Apr 2011
Location: QUEENS NY
Vehicle:
04 rex luger!

Default

^^ u can also clean it/ remove the gunk with maf cleaner. Just make sure its making the clicking sound unimpeded ..
danger1138 is online now   Reply With Quote
Old 03-10-2013, 07:30 PM   #17
CryderSpeed
Scooby Specialist
 
Member#: 88816
Join Date: Jun 2005
Chapter/Region: NWIC
Location: GET BACK
Vehicle:
TO TWERK

Default

PCV and O2 sensors are a another good idea. I'm probably going to just end up replacing a a bunch of stuff if my garage can't narrow it down to any one thing.

I did check to see if one wheel was hotter than the others indicating a sticking caliper, looks like we're OK there.
CryderSpeed is offline   Reply With Quote
Old 03-12-2013, 04:44 AM   #18
Cornerstore
Scooby Newbie
 
Member#: 328429
Join Date: Aug 2012
Default

Quote:
Originally Posted by CryderSpeed View Post
PCV and O2 sensors are a another good idea. I'm probably going to just end up replacing a a bunch of stuff if my garage can't narrow it down to any one thing.

I did check to see if one wheel was hotter than the others indicating a sticking caliper, looks like we're OK there.
+1!!!
Cornerstore is offline   Reply With Quote
Old 03-12-2013, 11:42 AM   #19
Barnt
Scooby Newbie
 
Member#: 161824
Join Date: Oct 2007
Chapter/Region: MWSOC
Location: Caledonia(Racine), Wisconsin
Vehicle:
2015 WRBP WRX
Cobb Stg 1

Default

Quote:
Originally Posted by bluemk3 View Post
No.. it's not...
yes...it is...
Barnt is offline   Reply With Quote
Old 03-14-2013, 10:10 AM   #20
shamrock 05
Scooby Guru
 
Member#: 120057
Join Date: Jul 2006
Chapter/Region: MWSOC
Location: *outskirts of motor city*
Vehicle:
2004 "Bugeye" WRX
WRB

Default

Quote:
Originally Posted by Barnt View Post
Fuel filter is inside the tank I believe
02-04 FF are in the engine bay, 05+ went to the fuel tank
shamrock 05 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -4. The time now is 11:22 AM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.