HORRIBLE MPG Help - Page 3 - JeepForum.com

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post #31 of 42 Old 02-06-2012, 06:17 PM
gebirgziege
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man, i get like 177-180 miles a tank.

06 LJ rubi

im on 33's and 4.10's at the moment.
front/rear bumpers, 10klb winch w synthetic rope.
all stock engine components. cat was replaced at 15k miles by stealership.
clean filter too. oil change last month.
something is up with mine too. i used to get 200+ miles.
id like a fix too.


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post #32 of 42 Old 02-07-2012, 05:16 PM
Tblack
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Quote:
Originally Posted by gebirgziege View Post
man, i get like 177-180 miles a tank.

06 LJ rubi

im on 33's and 4.10's at the moment.
front/rear bumpers, 10klb winch w synthetic rope.
all stock engine components. cat was replaced at 15k miles by stealership.
clean filter too. oil change last month.
something is up with mine too. i used to get 200+ miles.
id like a fix too.
Is this just recently? Winter blend gas will give you worse mileage. We have pretty strict emissions standards here in the salt lake valley. They blend the gas differently to accomodate for the temp so that we dont pollute the air too much. Any normal person doesnt know this, but if youre a mechanic or you have been through tech school, its one of the things that gets covered. That and it takes longer for the engine to reach opperating temperature, so it runs nice and rich until it reaches it. Soooo...... Millions of factors are working against you.

Safety 3rd!
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post #33 of 42 Old 02-08-2012, 05:22 AM
JPNinPA
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Quote:
Originally Posted by gebirgziege View Post
man, i get like 177-180 miles a tank.

06 LJ rubi

im on 33's and 4.10's at the moment.
front/rear bumpers, 10klb winch w synthetic rope.
all stock engine components. cat was replaced at 15k miles by stealership.
clean filter too. oil change last month.
something is up with mine too. i used to get 200+ miles.
id like a fix too.
You have something going on.

Calculate mpg not miles per tank.
Correct speedo?
When is the last time you cleaned the TB,IAC, changed Plugs, changed or cleaned the air filter?
Did they replace the O2 sensors when they did the CAT? Slow O2's will kill mileage.
Do you have an exhaust leak? After disturbing the exhaust often the flange bolts will loosen and the effect the O2 readings.
Did they reset the PCM? Will allow a relearn of new components.

"Never look down on anyone unless your helping them up"- Jesse Jackson
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post #34 of 42 Old 02-08-2012, 05:27 AM
misterpookie
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Originally Posted by FZY1 View Post
You Drive a Jeep, with the aerodynamics of a brick.
this^^^^^

i find i get about 15-17 and i think it's because i have the hard top/full doors. sure, it's more weight, but there's less drag.

http://www.jeepforum.com/forum/f9/po...-epic-1255803/ <--- my fuel economy thread. (which still needs more experimentation)
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post #35 of 42 Old 02-21-2012, 01:51 PM Thread Starter
Doubblea
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i was wondering if anyone would know if going to 410 ratio would be worse, or better for mpg? Since i dont know where it will put the rpms at. thanks

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post #36 of 42 Old 02-21-2012, 02:01 PM
flying_bosun
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Originally Posted by Doubblea View Post
i was wondering if anyone would know if going to 410 ratio would be worse, or better for mpg? Since i dont know where it will put the rpms at. thanks
4.10s should bring you closer to the proper RMP range. Grimmjeeper's gear calculator will answer your question(s) about where your RPM will be with any given setup.

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post #37 of 42 Old 02-22-2012, 06:10 AM
duhamel17
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I didn't see much improvement in mpg when I went to 4:10's with my auto tranny, but it did make a huge improvement in the felt power department. Well worth it imo.
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post #38 of 42 Old 02-22-2012, 07:44 AM
SpoiledRotten
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Fast cure for a Jeep Wrangler's gas mileage. Stop checking it! When it starts getting low of fuel, go get more. As many others have already posted in hundreds of threads, Jeeps aren't going to get the MPGs that a Honda Civic is going to get. And for the college kids whining about the cost to operate your Jeep, get a bicycle. Jeeps are a give and take kind of thing. You have to give up something to have one of the coolest vehicles on and off the road out there. "It's a Jeep thing" and you obviously don't understand.

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post #39 of 42 Old 02-24-2012, 04:28 AM
bdserv
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I have a 2003 Rubicon with 4-in lift and 33x12.50 tires, and stock 4.10 gears. Speedo has been checked with a GPS and is right on the money.

My daily driving is on somewhat hilly county highways and I was initially running in 5th gear whenever speeds were above about 40-45 mph and of course down shifting whenever the engine load required it. This would put the tach around 1500 to 1800 or so in cruise.

Driving this way had my gas mileage anywhere from 10 to 13 mpg.

After reading some posts here about running in 4th I decided to try this for a few tanks, staying in 4th as high as 55 mph with the tach between 2200 and 2400 rpm.

My mileage immediately improved - last tank was 17 mpg.

The engine does not feel like it is being lugged at all in 5th at these speeds, but there is no question that it is not as efficient at 50-55 mph in 5th as it is in 4th.

By the way, whoever designed that upshift light should resign from his engineering job in shame and disgrace!
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post #40 of 42 Old 02-24-2012, 05:58 AM
1999TJRED85000
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Quote:
Originally Posted by bdserv View Post
I have a 2003 Rubicon with 4-in lift and 33x12.50 tires, and stock 4.10 gears. Speedo has been checked with a GPS and is right on the money.

My daily driving is on somewhat hilly county highways and I was initially running in 5th gear whenever speeds were above about 40-45 mph and of course down shifting whenever the engine load required it. This would put the tach around 1500 to 1800 or so in cruise.

Driving this way had my gas mileage anywhere from 10 to 13 mpg.

After reading some posts here about running in 4th I decided to try this for a few tanks, staying in 4th as high as 55 mph with the tach between 2200 and 2400 rpm.

My mileage immediately improved - last tank was 17 mpg.

The engine does not feel like it is being lugged at all in 5th at these speeds, but there is no question that it is not as efficient at 50-55 mph in 5th as it is in 4th.

By the way, whoever designed that upshift light should resign from his engineering job in shame and disgrace!
It looks like the problem you have is 4.10 gears with 33" tires. 4.56 would be better in 5th.

BTW ... I just changed the air filter (stock), plugs, plug wires, coil, cap & rotor. I'll see what this basic tuneup does to the mileage.

F U
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post #41 of 42 Old 02-24-2012, 01:36 PM
4banged
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post #42 of 42 Old 02-24-2012, 07:04 PM
Griff1918
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The 4.0l power band is between 2200-2500 rpm its kinda like the sweet spot of the motor and let the engine warm up for like 10 min when its cold. Shift at about 2400 rpms that will gie your best mpgs
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