My 1996 Impreza AWD has been getting terrible gas milage. I've had the car for not quite a year now, and it's been doing this since I got it. Normally, it wouldn't be such a problem, but with gas prices over $2.20 a gallon here (For Regular - Ouch!) its starting to be a real pain in the wallet. I have tried just about everything. I replaced the air filter, plugs, wires, etc... I even ran some fuel injector cleaner through it. The fuel injector cleaner did make the car peppier and run better, but it did nothing for the gas milage. The only thing that makes a difference is running high octane gas. When I run Super 93 in it, the gas milage is fine, about where it should be. As soon as I switch back to Regular 87, the car goes back to its regular gas gulping self. I just can't seem to figure this one out. It runs fine on any octane rating but only gets good milage with Super 93. I have tried getting my gas at different stations but that has done no good either.

 

If anyone has any ideas they would be greatly appreciated.

 

Thanks.

Have you checked the timing? What is the MPG with regular gas?

Haven't checked timing but seems to run fine.

 

Will calculate MPG.

 

If problem continues will check timing.

 

Thanks.

Maybe it's time to replace the ECU temp sensor and the O2 sensor?

An automotive engine is not much more than an air pump. Make sure the intake and exhaust are not restricted in any way, including your air filter.

 

Jack

You should be happy that you are living in USA and not in Europe, here one litre petrol cost more than $1

1.40 here in DK

$1.80 in uk.Thats $7.50 a gallon for our american friends. Imagine that eh? That would make you pull your socks up!

well first off, you are aware subarus dont actually get the best of gas mileage right? Yes its a 4cyl, but you need to think its a V6 mileage wise. My guess is 24-26mpg would be your avg. My 93 gets anywhere from 21-26mpg depending on how much of it is freeway driving.

 

One good thing to check is your PCV valve, on most other motors this wouldnt make a huge diff mileage wise, but when mine crapped out, my mileage got stuck in the teens.

In Australia petrol is around $1.08 AUD per litre

 

 

 

You should be happy that you are living in USA and not in Europe, here one litre petrol cost more than $1

seen some gas mileage posts in the past. here's what just happened to me.

 

i was getting low gas mileage on my 2.2 liter impreza OBS....about 23/24 all highway miles. i did a tune up, new timing belts, rebuilt oil pump, cam seals, crank seals, spark plugs, wires, , fuel filter, PCV valve, etc. gas mileage went up maybe 1 mpg to 24/25. this was about 2 weeks ago.

 

then i replaced the brake pads just a couple days ago for a trip this past weekend and got excellent gas mileage. getting close to 30 mpg on one trip. i'd say averaged a solid 28 with the a/c on at least half the time.

 

either it took a couple trips for the tune up to *kick in* and improve gas mileage (i doubt it) or the brakes were causing a loss. brakes have always worked great with no problems at all.

sometimes the sliders that the caliper moves on gets jammed up, and you could have just free'd it up, causeing less rub. Or like the problem i had.. the pads were really hard to get in there, so i grinded off a little bit of the tabs on them, so they can move freely.

 

another note: i tried 93 octane ones, and i got worse milage, because subaru's don't have the high compression, where something running 93 would need the high compression to get the benifits of running on it.

Do you think it could be the timing? 'Cause that's what I'm starting to think. The knock sensor died on me about a month ago, and I replaced it. It still seems to run rough though, but only at idle. Just today it through another misfire code, probably the 5th one in the past few months. I've already replaced the spark plugs and wires, too. The air filter checks out. The O2 sensors could be a problem too, I suppose. Honestly, I'm stumped. My best guess is the timing theory.

shouldn't be timing as that really never changes assuming everythign else is nominal. you can unplug your O2 sensor and see how it drives. i unplugged mine and it won't affect highway mileage at all. done it a bunch of times.

 

how about the ignition pack?

Thanks.