Solving poor Subaru mileage

[ediamiam]

How about some history. How many miles on the car? Did you buy it new or used? Was the mileage always low, or did it drop at some point in time? Have you always used xxw30 oils, or have you used xxw40 at some point? What air pressures do you typically run with in the tires vs recommended? Also, what kind/brand of gas are you using, anything with alcohol, methanol? Does the engine consume oil, if so at what rate? Have you considered arx or fp?

[ August 30, 2005, 01:08 PM: Message edited by: ediamiam ]

 

[Leo]

I reckon maybe an ECU reset might change things. Warm up the car and then pull the negative lead from the battery and wait a couple of minutes. Then replace it, start her up and let her idle for a minute or so. Now go for a 10 minute drive using mainly light throttle so the ECU can relearn its fuel trims. See how you go with that...

 

[Eddie]

To reset the ECM remove the neg battery cable and push the brake peddle several times to fully discharge the system. Just pulling the batt cable for 10 minutes will not reset the ECM.

 

[bfg9k]

Thanks for all the tips everyone. This morning's fillup was $2.77/gal, and I'm still stuck at 21.2 mpg.

I have the autorx on order, and I will reset the ECU today. Examining the fuel system end-to-end will wait til this weekend. I really appreciate the advice and expertise!

 

[Eddie]

Don't forget to count the gears to make sure the transmission is shifting to top gear and torque converter is locking up.

 

[n8wvi]

Uh..... We had a '99 Legacy w/ the 2.2L 4sp auto. We averaged about 28mpg. If all wheel drive suck gas, Subaru must be doing something better than other vehicles. My '97 Impreza averages 32mpg w/ 142,000 miles on it.
Even my wifes 3.0L Outback averages 26mpg.
Something IS wrong with your car. Are you sure your new thermostat is working properly?

Dave

 

[John K]

These Subs are all AWD, so the EPA ratings are for the right model. I had a 98 Legacy GT 2.5, never could get more than 25 mpg.(Don't remember EPA rating, think 27 or 28 highway) I'd try 3 psi higher in the tires, and track down source of gas smell.

 

[Ed_T]

I had an 04 Forester loaner, that at legal speeds on the xway, I could watch that gas guage sink like the Titanic.

The car ran great but what a pig.

 

[Tosh]

OK, I don't know what I'm talking about (this time), but on Cartalk a few months ago, a lady had an odd intermittent problem on her Subie (stalling at highway speeds when hot, forgot which model), and they said straight away 'ignition module is known to be weak on that car.' Take that for what it's worth...

 

[Jim Spahr]

Smell of gasoline may mean a leaking fuel injector. Get the injectors checked. There are shops that exchange rebuilt injectors for your old ones at a resonable price. Bump up the tire pressure 2 to 4 lbs like John K said.

 

[2002 Maxima SE]

What did you find?

 

[bfg9k]

Hi all,

I have experienced a 3 mpg increase (up to 23 mpg) since I replaced the engine temp sensor.

I have examined the fuel system very carefully and have not found any signs of leaks. I found a fluorescent gasoline dye:
http://www.autobarn.net/tratp3400060.html
and may talk with my mechanic about giving something like this a try in order to completely rule that out.

I am now suspecting that there may be a leaky fuel injector. I guess I can either get 'em cleaned or replaced like Jim Spahr suggests. I am considering replacing the car with a low mileage '97 Saab 9000 for sale locally (I'm a Saab junkie, what can I say?) so I will mull over putting any major $ into the Subaru.

I'll bump up the air in the tires this afternoon, it's been a few weeks since I last checkd them and the weather is cooling so it's a good time to do that.

Thanks for all the help everyone. I will report back in a few weeks.

 

[seotaji]

have you thought about cleaning the car's EGR system?

i did that to mine and netted a nice increase.