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HORRIBLE Gas Mileage

B

black2door

NAXJA Forum User
Location
Spfd. MO
Hey guys, I've only had my jeep for like 2 1/2 months, The other day I filled up and decided to figure my mpg. I knew I wasnt getting great but never expected this low. I drove 12 miles and burned close to 1/4 a tank....WOW!! It has been cold and snowy but does that make that much of a difference. I dont drive it hard at all. I drove it all in the city stop and go. Never really went over 30. I know I need to do a tune up, but this seems like something else could be wrong.
1997 Xj AX-15 4x4 4.0L
 
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I have a 4" lift and 32" mud tires with a Rack on top and I get about 16mpg, I run around in 3rd, never use overdrive even on the freeway. When I was using Overdrive I was onloy getting like 14mpg. Running it in 3 I dont have to mash the gas as hard.
 
Do the tune up first,don't be cheap,get plugs ,wires,whatever you need.Also wouldn't hurt to change the O2 sensor,it helped a couple of my cars a lot.See if you can find a can of BG44K and add to your gas,amazing stuff.:D
 
As I said amazing stuff,I had an 88 with 185,000 on it ,hard miles with little maint.Ran a can down the interstate at 80+ and got 3 more mpg and it smoothed out and ran great.I would say every 2nd or 3rd oil change would be fine:)
 
safn1949 said:
As I said amazing stuff,I had an 88 with 185,000 on it ,hard miles with little maint.Ran a can down the interstate at 80+ and got 3 more mpg and it smoothed out and ran great.I would say every 2nd or 3rd oil change would be fine:)
Click to expand...

someone needs to post a link with this stuff up. actually...ebay wins!
 
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I get 10-14 mpg, depending on time of year (temperature).......3.55 ratio w/ 30's.....

Don't drive hard when the engine is still cold. It is really not efficient when cold and therefore will suck gas.
 
First off, you can't make any good asumptions about gas mileage without running at least a full tank of gas. The gauge is not linear.
 
x2 on the not driving cold. I know that sometimes your in a rush, dont have time to start early in cold weather, just jump in and go.(girlfriend does it all the time) i read somewhere that a cold engine is 1/2 as effiecent, (burns 2x as much fuel) and wears twice as fast.

i know now im just venting now but abother thing the girlfriend does is let it warm up(when she does) the just gun it. people think engine is warm so your good to go. think of all other parts that are still cold. ( diffs,axles,u joints,trans, suspension components etc etc etc.)
 
The reason for cold engine bad mileage is simple. Its a fuel enrichment factor, the ECU runs the engine rich during warmup taking coolant temp readings from the IACV. Basics of any EFI system.

The remote start idea is a good one, I needa get me one of those.
 
I have a competely stock 97XJ Sport with 4.0L, AW4 and NP231, 145k miles, daily driver, some towing. After I got it I was getting mpgs from 12 (lots of idleing) to 15 around town. This past spring I replaced the following : sparks, plug wires, distrib cap, oil, coolant, air filter, belt, water pump (do they actually have a designed life of only ~150k?). Long story short, I can reliably get 17/21, which was a nice improvement when gas went to $3.15. Keep in mind that the sticker (at least for my model) says 15/18. Only other thing I know would help is a tranny and transfer case fluid change, maybe even the diffs.
 
again how many guys with lifted rigs etc have changed the speedo gauge .. I thought i was getting terrible gas mileage till i factored how far off my speedo / odometer was off .. example I know for a fact my house to work taking hte normal path is 23.8 miles . once i lifted and went to bigger tires suddenly my odometer showed it being only 18.3
 
Capt. Jack said:
I have a competely stock 97XJ Sport with 4.0L, AW4 and NP231, 145k miles, daily driver, some towing. After I got it I was getting mpgs from 12 (lots of idleing) to 15 around town. This past spring I replaced the following : sparks, plug wires, distrib cap, oil, coolant, air filter, belt, water pump (do they actually have a designed life of only ~150k?). Long story short, I can reliably get 17/21, which was a nice improvement when gas went to $3.15. Keep in mind that the sticker (at least for my model) says 15/18. Only other thing I know would help is a tranny and transfer case fluid change, maybe even the diffs.
Click to expand...

You should have seen my water old water pump it was leaking when i removed it and looked at the blades of the wheel that pumped the water they were totaly corroded (aluminium) as if i was using Sulfuric Acid as coolant.
 
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old_man said:
First off, you can't make any good asumptions about gas mileage without running at least a full tank of gas. The gauge is not linear.
Click to expand...

x2.

Gas mileage is best estimated over several tanks. Everything will average out better therefore giving a more accurate MPG.
 
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