My fuel mileage sucks...

[CoastieJ]

Obviously the price of gas these days is killing everyone. I just bought a '96 XJ, completely stock, well maintained (have all the records). I get 12-13 mpg consistently...what's up with that? I've changed the fluids and dropped in a Fram Air Hog reusable filter. It steers straight, runs great, idles well, air is good in the tires, I drive like a grandma and still no change.

Any ideas? Was thinking some new spark plugs, hi flow wires, headers, cat, and exhaust might open things up a bit. Got any ideas?

 

[Pete M]

Clogged cat maybe? How healthy does the engine feel when you accelerate hard? Stock sized tires right? How many miles on the Jeep?
--Pete

 

[96 Cherokee]

Obviously the price of gas these days is killing everyone. I just bought a '96 XJ, completely stock, well maintained (have all the records). I get 12-13 mpg consistently...what's up with that? I've changed the fluids and dropped in a Fram Air Hog reusable filter. It steers straight, runs great, idles well, air is good in the tires, I drive like a grandma and still no change.

Any ideas? Was thinking some new spark plugs, hi flow wires, headers, cat, and exhaust might open things up a bit. Got any ideas?

Something is real wrong here. I get better mileage than that on my rural mail route. That's about 420 boxes on a 90 mile route. Mine does close to 20 mpg on DD type driving, and about 23-24 mpg on the interstate. When it was newer I could get 25 on the interstate.

 

[Pioneer89XJ]

I am lucky to get 15 mpgs w/ all city driving. 20 or so on straight highway driving.

 

[MudslinginXJ]

Sorry to hi-jack but im curios too. I've got a 4.0 w/ aw4 and i was getting 17 around town and it dropped to about 13-14.

 

[mikejwil]

I've heard that a sudden drop in MPG is a sign that the O2 sensor has gone bad. Can anyone confirm this? How many miles do you guys have on your O2?

 

[Tally_XJ]

It could be O2 sensor, or even the MAT (manifold air temp sensor), also called air charge sensor.

 

[mgreen84]

FINALLY I DON'T FEEL ALONE, mine gets 12 mpg if I'm lucky, and I have replaced EVERYTHING, possible. I have a xtreme flow cat on mine too!!

 

[mgreen84]

shouldn't the O2 send an idiot light (engine light)

 

[XplodJeepster]

never count on idiot lights. my friends mother has a nissan pathfinder and the check engine light comes on all the time. she stops, opens all the doors, and then closes them again, no more c.e.l.

thats how reliable those idiot lights are.

 

[90Pioneer]

Obviously the price of gas these days is killing everyone. I just bought a '96 XJ, completely stock, well maintained (have all the records). I get 12-13 mpg consistently...what's up with that? I've changed the fluids and dropped in a Fram Air Hog reusable filter. It steers straight, runs great, idles well, air is good in the tires, I drive like a grandma and still no change.

Any ideas? Was thinking some new spark plugs, hi flow wires, headers, cat, and exhaust might open things up a bit. Got any ideas?

I'm in the same boat. I have a 96 XJ with 79k, mostly stock and well maintained. I get between 11 and 13mpg. I run Ams synthetic with a new cap, rotor, wires, plugs, front O2 sensor, air filter, trans & diff serivce, fuel filter, and a can of GM top end cleaner ran through her. No change in mileage before or after all of this.

 

[mgreen84]

We can always swap in a hefty pull start, 12 horse, briggs and stratton. Bore it out and put a little header on it, who knows may hit 6....or 7 Miles Per Hour.
(SOUNDS LIKE A PLAN TO ME )

 

[TacticalFats]

I just tallied up my mileage figures since April. Only three tankfuls weren't logged (wife).

My average is about 13 MPG.

97 auto, 89k, all stock (slightly bigger tires), well maintained.

WTF.

 

[langer1]

Very intresting thread, my 87 ave 21 with plain gas. I have seen what I think was poorer mileage on some fuel. I use Citco because it's close but I swear when I get Shell my mileage it even better, and BP suckes.

Post your mileage and the gas you burn.

 

[old_man]

Run a can of BG44K every 10k miles. Injectors get clogged and inefficient. You will see a difference immediately. It also cleans carbon off of the valves and pistons.

Crappy O2 sensor can also cause headaches, but the clogged injectors over time seem to be very common.

 

[XJ88User]

I'll have to go with the injectors also, I was getting at best 14 then did a swap out of all of mine with Ford injectors from advice from this board, next tank of gas I was getting just about 19.
Mine were very fouled when i took them out, plus I suspect i had a leaking one because my oil always smelled very heavly of gas and was very thin.

 

[2XJ]

What is this, Old Man? Fuel Injector Cleaner? Where do you find it?

"Run a can of BG44K every 10k miles. Injectors get clogged and inefficient"

I have heard of top engine cleaner - is that what you are referring to?

 

[red91]

What is this, Old Man? Fuel Injector Cleaner? Where do you find it?

"Run a can of BG44K every 10k miles. Injectors get clogged and inefficient"

I have heard of top engine cleaner - is that what you are referring to?

go to BG44K's web site and look for a dealer in your area....I got the package with the can of BG44K and gas drier for about $28.00.

Worked wonders.

Need to do so again.

most cleaners in PLASTIC will not do what they say. If it's supposed to clean carbon off what do you think it would do to a placstic bottle ?

BG44K is good junk.

 

[langer1]

I did a search on the BG website and here in Ohio there's only one dealer within 100 miles and their known to be crooks. That don't mean the stuff don't work but at $20.00 I have a feeling it's snake oil. JMO

 

[Maz]

Run a can of BG44K every 10k miles. Injectors get clogged and inefficient. You will see a difference immediately. It also cleans carbon off of the valves and pistons.

Finally found and tried a can of BG44K, last month, with much anticipation. Didn't feel any improvement in performance, and, didn't gain any gas mileage (15mpg). Much disappointed.
-Maz