Is this unacceptable fuel mileage?

[987687]

I have a 98 LGT limited with a 2.2 swap, automatic transmission, and 245k miles on it.

It gets around 24mpg, I live in rural nowhere. I make very few stops, but most of the roads are 45-60mph and hilly. So lots of shifting up and downhills, TQ in and out of lock, curves, etc.

 

I was talking to someone who said 25 is unacceptably low for my car with these driving conditions, but I've always just accepted it as somewhat normal.

Even if I'm on a long highway road trip (interstate driving), it still gets right around 25.

 

I've always just accepted this is what you get with an old auto tranny car... but is this too low?

(and yes, my odometer reads correctly, I have stock size tires, and I know how to do math)

If everyone thinks it's too low I'll start checking O2 sensors, etc.

[AdventureSubaru]

Sounds about right. You'd be amazed what hills/downshifts do to fuel economy. We used to have this Ford Ranger that could get close to 30mpg on flat highway. Went through the smoky mountains and the little 4cyl engine was chugging to get over the hills. Went down to about 14 mpg on that stretch. For a 2.2 with that big automatic trans, AWD, biggish car for the power and hills, I'd say you're right on.

[ivans imports]

Check tire preshures i run 35 front and 32 rear also check feul fillter a pluged one will drop milage i c thiss alot causes the feul preshure to run to high when you dont demand and not enuff under demand. All the ej subarus i c get 300km on 30$ consistantly at 135-140 a Liter. Check filler spout is not leaking likes to leak above half tank if bad.

[987687]

Tire pressures are fine, fuel filter is fine, I've eradicated all fuel leaks.

[mattocs]

That's a decent fuel mileage. I average 22-26mpg on my 2.2s. I could get 30mpg on the highway, and I get in the upper teens in short distance and stop and go traffic. I'm usually content as long as my average is 22mpg or better.

[Recian]

Actually that does seem a bit low. My 95 auto awd 2.2 gets mid to upper 20s around town and my tranny is going out. Dont forget the basics, fuel/air filters, plugs/wires. Check all vacuum hoses for cracks, any intake leaks will trick the car and make it burn more fuel. Is the car running any more sluggish than usual? This could be due to dirty MAF or t-body, restricted exhaust like a collapsed cat. Also when was the last time you changed the trans fluid? the automatic trans can seriously hinder power put to the ground and reduce economy if its fluid doesnt function properly. Hydraulic fluid is sensitive and will break down with time and should be changed every few years even if you dont hit 30k miles.

[987687]

I installed the current engine probably 3 months ago.

I made sure I didn't have any vac leaks, fresh air filter, clean MAF, etc.

The car is about as peppy as you could expect from a 2.2 auto, it's as fast as other ones.

I doubt it has an exhaust restriction.

Last year I did three tranny fluid changes with a couple days of driving in between, then I changed the filter and did a 4th. Made sure to use all the positions of the gearselect, etc. It's currently at the correct level with a nice red color. It also leaks a bit (from probably more than one place...). So It gets about 1 fresh qt a month. Front diff got fresh gear oil around the same time, still the same nice color as it was when I changed it. The rear diff has 56k miles on it with synthetic. So that's nice and fresh.

[Recian]

Then i'd check the knock sensor and try different gas stations. My sensor was melted when I bought my car so while I had my heads off i replaced it with a OEM one. Cost me $95 but i have 0 knock/spark on 87. I hear they cause alot of issues and fail often on 90s model suby's. Lots of stations now use so much ethanol or alcahol past the 10% youre supposed to be informed of.. My 89 buick I had before my impreza was rated at 18city 28hwy. I NEVER got 28 hwy, only about 25 and averaged 20. since the gas now is so watered down with alcahol or ethanol cars rarely get the MPG posted on the stickers anymore, at least older cars. Their computers cant compensate for the unburnable substance. In a way it's like running with EGR opened all the time. It's not as bad where im at but I try to use HESS or local mom and pop type stations. Those usually have less ethanol. Easy way to check your fuel. Pull the line off and turn the car on and put some fuel into a 20oz drink bottle. Dont fill past 1/3 way. Mark where the fuel was and add about 1-2 oz of water then mark it again. Then shake, but dont get too aggressive or it will explode. Then let it sit a few mins. The water will mix with the alcahol or in some cases water then sink to the bottom. if there's a noticable difference between the new amount and the lines you marked (say your marks were 1/4" apart and there's 1" or so at the bottom then that's the issue.

[987687]

Interesting about testing the fuel in a bottle with water. Never heard of that, I'll have to give it a go!

 

I really doubt it's the knock sensor. When I got the car, the service records showed a new knock sensor just 1500 miles before I got it. So it probably has 35k miles on it now and only 2 years old. When I swapped it to my current engine I cleaned up where it mounts to the block. And checked the sensor, the wire is fine and it's not cracked.

[Gloyale]

Perhaps new plugs, new o2 sensor and such could help.

 

But honestly, 24 sounds decent for an auto trans car.

[GeneralDisorder]

My most recent trip with a 2.2 was in a '96 Outback 5MT - over the mountains headed from Portland to K-falls the car got 27.5 and then on the way from there to Reno, NV it was almost 29.

 

For around town driving you are about right. But for long freeway trips you should be quite a bit higher.

 

GD

[987687]

My most recent trip with a 2.2 was in a '96 Outback 5MT - over the mountains headed from Portland to K-falls the car got 27.5 and then on the way from there to Reno, NV it was almost 29.

 

For around town driving you are about right. But for long freeway trips you should be quite a bit higher.

 

GD

 

My 96 5mt got about that. I just figured the auto will be lower because it's an auto.

 

Plugs and wires are new within the last year. Only thing I haven't touched is the o2, so maybe I'll replace that.

It doesn't throw a code, but that doesn't mean it's not tired and responding slowly or whatever.

[smiffy6four]

Your mpg sounds about right; I live in similar terrain, drive a 99 2.5 auto Forester and get 25mpg locally, and 30 on a highway run.

[Fairtax4me]

I managed to get 27 out of my 95 wagon automagic 2.2 on my latest highway trip. That's the best I've ever got out of that car. I live in the same type of area. Lots of hills, up and down and slowing for curves. I usually get around 22-23 mixed and high teens just in town.

[Recian]

If ur getting 24 in a hilly area then yea that does sound good. Where im at its flat thats probably why i get a bit more. Plus in town isnt very bad stop and go usually i drive hwy back roads to work so i get around 27. The water bottle trick i was taught by nissan tech line. U wouldnt believe how many cars i get at work with over 10% ethanol that cause them to run like s**t. Theyre trying to force 15%. That much will eat your engine alive from the inside out.

[bratman18]

I have to say that I'm the one that told 987687 that I didn't think this was good mileage. I have a 98 Forester auto, with 27.5" tires and I easily get 30, if not more at times. It's all pretty much rural driving, no highway. Another family member of mine gets 30+with his 98 Outback 5spd. It just seems low to me.

[987687]

How do you calculate?

[bratman18]

Set my trip when I fuel up, and the check it when I fill up again...........And my speedometer is spot on with the tire size.

[CoupedUpSubie]

I would say that 24-25mpg for a 2.2 with an auto sounds about right. The GT auto trans has a 4.11 final drive. The 96 outback 5MT is a 3.9. With different gear ratios and such your fuel mileage will change.

 

My 1.8 fwd is having a hard time hitting 30 mpg lately.

 

Fuels are getting more ethanol which as many have said is not good. From the good trusty 5hp brigs and stratton lawn mower engines to trucks I have seen ethanol mess systems up and drop power and fuel mileage.

[987687]

I would say that 24-25mpg for a 2.2 with an auto sounds about right. The GT auto trans has a 4.11 final drive. The 96 outback 5MT is a 3.9. With different gear ratios and such your fuel mileage will change.

 

My 1.8 fwd is having a hard time hitting 30 mpg lately.

 

Fuels are getting more ethanol which as many have said is not good. From the good trusty 5hp brigs and stratton lawn mower engines to trucks I have seen ethanol mess systems up and drop power and fuel mileage.

 

Actually, the 96 outback with 2.2 has a 4.11 final drive with the 0.78 5th gear, and the GT/OBW/fozzy automatic has the 4.44 final drive.

[subaruplatt]

Your car probably weighs more than less safe vehicles remember that.

 

If your not going more than 40 miles per hour you can leave it in third. Mine hunts, at speeds past city but not yet highway sometimes.This transmission has a problem with this in-between range.

Sounds like it's the uphill trek that really does you. It's not like a hybrid when you have gained something going down.

Sometimes when the car is warm I can drive up hill and it will not down shift into third and sometimes it does.

As an aside I learned that one can shift the auto without disengaging the cruise. I have done so into third to add extra engine breaking downhill on logging roads.

 

I believe that the car will never lock the torque converter if the temp sensor thinks it's cold. With mine the torque converter is loose until the car is warmed up, to encourage revving and rapid warming of the engine.

The only other things are tires i.e. low mpg tires, break drag.

Not sure if fresh bearings do much, hell maybe old cv joints eat up energy.

Hell maybe there is a brand or form of cv which is more efficient than the other?

[CoupedUpSubie]

There is still the factor that the engine will run at different RPMs for your speeds which is what mostly causes excess fuel usage from one car to another. Your getting more performance out of your 2.2 with the auto trans then say someone with the 4.11 or 3.9 FD manual trans.

[bratman18]

There is still the factor that the engine will run at different RPMs for your speeds which is what mostly causes excess fuel usage from one car to another. Your getting more performance out of your 2.2 with the auto trans then say someone with the 4.11 or 3.9 FD manual trans.

 

Yes but it can also be looked at as the engine isn't working as hard with the lower gears to get up to speed.

[987687]

My 96 with 2.2 and 3.90 final drive 5speed had more pep accelerating.

Forget final drive for a moment... With the 3.90 5speed 2nd gear topped out at maybe 50, first at around 25 or so? With the auto first tops out around 35 and 2nd at 60.

So that means with the 5speed it would accelerate faster because it needed to go through more gears to get to the same speed. Meaning it was in the powerband more often. Then forget acceleration once the auto shifts into third, hello brick wall. 3rd tops out around 100, it's slow as hell. I'll take a 3.90 5speed any day.

 

That means normal acceleration with the auto it's revving higher, then shifting to a lower not as efficient RPM to get up to speed. The 4.44 doesn't mean anything besides it's better than the auto with the 4.11, and even that has different gear ratios, it has shorter gears to help make up for the longer final drive.

[ivans imports]

Hey at least you know your injectors are moving feul but mabee there not stoping had one when i did the heads the injectors kept driping feul after engine was shut off intake was still atached to car and it just sat there driping feul the injectors were faulty a problem like thiss whould make for bad malaige would use gas just sitting you can get bad milage not even driving