Exceptionally poor gas mileage

pankracy · 04-07-2005, 08:11 AM

I just got my first Jeep, 2004 X, 5 speed, all stock with 8500 miles on it... I've gone through five or six tanks and my gas mileage comes out to be more or less 11 MPG!!! I drive it so gently that only standing still make sit burn less gas, never above 2000rpm, down the hill in neutral, etc... There doesn't seem to be any mechanical drag, wheels spin easily while on a lift, I'm not packing my in-laws in the b ack so i keep the weight to its minimum...

Can anyone help out?

b3x · 04-07-2005, 08:17 AM

sell it and buy a honda civic ... garaunteed better gas mileage

jmcgonig · 04-07-2005, 08:18 AM

What type of driving do you do? City or Highway. What speed do you go on the highway?

pankracy · 04-07-2005, 08:22 AM

I'd like to keep my Jeep so Honda is ou tof the question for now.

I do both city and highway, more hwy though and on the hwy 55 at most since it feels like i'm doing 80 with all the noise with the soft top and all...

From what Jeep is advertising i should really be getting at least 15-17 MPG or more...

jmcgonig · 04-07-2005, 08:30 AM

Your not going to get 15-17 in most cases. Try shifting at a little higher rpm. If you always keep it under 2k your lugging the engine which can take more gas. Shift at 2500 or so and see what changes.

KaiserJeep · 04-07-2005, 08:31 AM

Are you sure the original owner did not fit larger tires? If so, the speedometer could be way off, and any calculations of mileage likewise inaccurate. What size tires are presently installed?

pankracy · 04-07-2005, 08:36 AM

Shifting at 2500, i'll give it a try... i may be beating on it while below 2000

Tires are stock 225/75R15 on alum rims, i think it's a standard option from jeep.

Just the other day I asked someone on the street in their Jeep what kind of mileage they get and they're telling me 19!!! Maybe 2.5liter engine does better than my 4L?

rhelton04 · 04-07-2005, 08:38 AM

Quote:

Originally Posted by jmcgonig

Your not going to get 15-17 in most cases. Try shifting at a little higher rpm. If you always keep it under 2k your lugging the engine which can take more gas. Shift at 2500 or so and see what changes.

Agreed. Keeping it under 2k is certainly lugging it. I try to keep mine in the 2-3k range and that seems to be the "sweet spot". With 31" tires and 3.07 I'm getting consistent 16-17 mpg.

jmcgonig · 04-07-2005, 08:43 AM

Could also be gears. 3.07 will get better gas mileage than 3.73s on a stock jeep.

**Jerry Bransford** · 04-07-2005, 08:44 AM

Not to imply you're miscalculating your mileage, but how are you calculating it? I've heard of some strange ways of miscalulating fuel mileage.

dstandiford · 04-07-2005, 08:48 AM

Quote:

Originally Posted by Jerry Bransford

Not to imply you're miscalculating your mileage, but how are you calculating it? I've heard of some strange ways of miscalulating fuel mileage.

While we're on the subject I thought it was from the time you left the pump to the time you come back divided by your capacity.... thats a rough estimate anyway... am I correct?

rockrawling43 · 04-07-2005, 08:49 AM

I keep mine right around 2500 RPM, thats where it seems to like. I dont even know what my gas milage is. Never really worried about it, but I expected horrible milage going into it. I get a little worse cause I have 32" x 11.5 tires. Didnt buy it for its wonderful gas milage. Just have fun and enjoy it for what it is, not for what it lacks.

pankracy · 04-07-2005, 08:50 AM

This is getting better and better...

First how do i change gear ration, do i need to replace whole rear axle or just gears inside of it.

I calculate my MPG in the following way:
1. Fill up the tank all the way
2. Reset trip meter
3. Drive until almost empty and refill to the top
4. Get miles driven and divide by amount of fuel poured in at refill (200/17.5=11.4MPG)

I know i can be off by a fraction if i only pour a little more or a little less at each refill but that's only a fraction...

**Jerry Bransford** · 04-07-2005, 08:56 AM

Quote:

Originally Posted by pankracy

1. Fill up the tank all the way
2. Reset trip meter
3. Drive until almost empty and refill to the top
4. Get miles driven and divide by amount of fuel poured in at refill (200/17.5=11.4MPG)

Well that's how to do it, no problem there. Nope, the 2.5L does not usually get significantly better mileage than the 4.0L does except in lab test conditions. Those with 2.5L engines have to drive them so much harder to keep up with traffic that they lose the potential mileage benefit.

11mpg is pretty low, I don't even get that low with my built Jeep (12-13 mpg). I dunno, maybe your upstream (nearest the engine) 02 sensor is bad. Have you ever gotten a check engine light? Air filter clean? Not lugging your engine by driving at too low rpms too often?

fansipans · 04-07-2005, 08:59 AM

Wow, sounds like something's wrong.

What is the average length of the trips you take in your jeep? If you only ever go a few miles and never give it time to warm up, you'll just be running in Open Loop (no engine management!) and you'll get correspondingly HORRIBLE gas mileage.

I experienced exactly that when my thermostat was stuck open and my engine had a constant flow of coolant, the temp gauge never got above 130, so I stayed in Open Loop wherever I drove... sure enough got about 11mpg before I swapped t-stats

04-07-2005, 08:49 AM	#12
rockrawling43 Registered User Join Date: Apr 2005 Posts: 101 Profile Gallery Classifieds My Jeeps	I keep mine right around 2500 RPM, thats where it seems to like. I dont even know what my gas milage is. Never really worried about it, but I expected horrible milage going into it. I get a little worse cause I have 32" x 11.5 tires. Didnt buy it for its wonderful gas milage. Just have fun and enjoy it for what it is, not for what it lacks. __________________ Real Jeeps are rhino lined

04-07-2005, 08:59 AM	#15
fansipans Registered User Join Date: Mar 2005 Location: Manassas, VA Posts: 43 Profile Gallery Classifieds My Jeeps	Average Distance Traveled? Wow, sounds like something's wrong. What is the average length of the trips you take in your jeep? If you only ever go a few miles and never give it time to warm up, you'll just be running in Open Loop (no engine management!) and you'll get correspondingly HORRIBLE gas mileage. I experienced exactly that when my thermostat was stuck open and my engine had a constant flow of coolant, the temp gauge never got above 130, so I stayed in Open Loop wherever I drove... sure enough got about 11mpg before I swapped t-stats __________________ '98 TJ 4.0

04-07-2005, 08:22 AM	#4
pankracy Registered User Join Date: Apr 2005 Location: Essex County, NJ Posts: 9 Profile Gallery Classifieds My Jeeps	I'd like to keep my Jeep so Honda is ou tof the question for now. I do both city and highway, more hwy though and on the hwy 55 at most since it feels like i'm doing 80 with all the noise with the soft top and all... From what Jeep is advertising i should really be getting at least 15-17 MPG or more...

04-07-2005, 08:36 AM	#7
pankracy Registered User Join Date: Apr 2005 Location: Essex County, NJ Posts: 9 Profile Gallery Classifieds My Jeeps	Shifting at 2500, i'll give it a try... i may be beating on it while below 2000 Tires are stock 225/75R15 on alum rims, i think it's a standard option from jeep. Just the other day I asked someone on the street in their Jeep what kind of mileage they get and they're telling me 19!!! Maybe 2.5liter engine does better than my 4L?

04-07-2005, 08:50 AM	#13
pankracy Registered User Join Date: Apr 2005 Location: Essex County, NJ Posts: 9 Profile Gallery Classifieds My Jeeps	This is getting better and better... First how do i change gear ration, do i need to replace whole rear axle or just gears inside of it. I calculate my MPG in the following way: 1. Fill up the tank all the way 2. Reset trip meter 3. Drive until almost empty and refill to the top 4. Get miles driven and divide by amount of fuel poured in at refill (200/17.5=11.4MPG) I know i can be off by a fraction if i only pour a little more or a little less at each refill but that's only a fraction...