Higher City MPG than Highway

[JeepKiller]

So lately I've been getting a LOT better city mpg than highway.... Today I got 8mpg on nothing but highway while yesterday I drove city all day and got around 15. Is there something horribly wrong? I know I've got a substantial lift, lights and weight but I wouldn't think that city would be better than highway... Anyone know of a potential cause for this bad of gas mileage?

 

[gergg]

So lately I've been getting a LOT better city mpg than highway.... Today I got 8mpg on nothing but highway while yesterday I drove city all day and got around 15. Is there something horribly wrong? I know I've got a substantial lift, lights and weight but I wouldn't think that city would be better than highway...

My truck is lifted(SS 1.2) and on 285 75r16....I have been getting 15mpg around town and got 19.4mpg on a recent 250 mile hwy trip 65-70mph.

 

[4-Ripcord]

Were you towing a house? If not its time for a big tune up.

Try this:

3rd Gen 4Runner Buyer's Guide: Tune up section

 

[7echo]

How are you calculating the mileage?

Some examples of these trucks have known issues with fuel gauges.

 

[JeepKiller]

How are you calculating the mileage?

Some examples of these trucks have known issues with fuel gauges.

My fuel gauge has always been fairly accurate. I'm using miles driven based off maps and my gauge. I've done it numerous times using both 1/2 a tank and 1/4 a tank, it's always around 8 mpg highway.

 

[gergg]

My fuel gauge has always been fairly accurate. I'm using miles driven based off maps and my gauge. I've done it numerous times using both 1/2 a tank and 1/4 a tank, it's always around 8 mpg highway.

Sorry if I am stating the obvious, but guess you could verify your mpg by the old method....fill to the top with gas, drive until you need more gas, add gas to the top again, divide miles driven by the gallons added to get actual mpg.

 

[JeepKiller]

Sorry if I am stating the obvious, but guess you could verify your mpg by the old method....fill to the top with gas, drive until you need more gas, add gas to the top again, divide miles driven by the gallons added to get actual mpg.

I've done that as well, I'm just saying that I've tried other methods as well. I can almost watch my gas going away.

 

[azcat90]

What does the tach read at 65mph?

 

[gergg]

I've done that as well, I'm just saying that I've tried other methods as well. I can almost watch my gas going away.

I am not a mechanic so take this for what it is worth.....I noticed last week my mpg's were way down(coincidentally around 8mpg), I found a little vacuum leak so I fixed that hose and cleaned my MAF, mpg's are back to normal....not sure if that is helpful, but figured I would mention it.

 

[JeepKiller]

What does the tach read at 65mph?

Rpms are around 2300 at 65 and [MENTION=126994]gergg[/MENTION] thanks, I'll definitely check for vacuum leaks and I just cleaned my maf last month but I guess it can't hurt. I may try replacing the fuel filter and see if that helps.

 

[Rock_Rat]

You may want to try leaving your ECT on and deselecting your OD anytime you're under load on the highway. I've been using this quite successfully allowing me to keep my foot out of the throttle just going up hills on ramps, etc. Straight and level I'll engage OD and de-select ECT. I'm averaging about 17mpg with the similar weight you have. My biggest hit is the last few miles home. I live on a mountain. I know that 8mpg is pretty low so I think there's something else going on there but the fact that your MPG is good in the city is puzzling.

 

[4xt4r]

So lately I've been getting a LOT better city mpg than highway.... Today I got 8mpg on nothing but highway while yesterday I drove city all day and got around 15. Is there something horribly wrong? I know I've got a substantial lift, lights and weight but I wouldn't think that city would be better than highway... Anyone know of a potential cause for this bad of gas mileage?

Do you have to press the gas pedal more to maintain HWY speeds now compared to when you were getting decent mileage?
I'm wondering if you have a "breathing" restriction, maybe a restricted cat or muffler.
a restriction driving in town might not be as noticeable as when on the highway .

 

[SilverRidgeRunner1]

I would be interested to see what your Long term and short term fuel trim looks like

 

[JeepKiller]

Do you have to press the gas pedal more to maintain HWY speeds now compared to when you were getting decent mileage?
I'm wondering if you have a "breathing" restriction, maybe a restricted cat or muffler.
a restriction driving in town might not be as noticeable as when on the highway .

Nope, my driving habits have actually improved... Which is really weird [MENTION=110088]SilverRidgeRunner1[/MENTION] I'm not huge on technical terms haha so do you mean my short term mpg vs long term? Because I've been getting a solid 8 mpg for the past month.

 

[SilverRidgeRunner1]

Nope, my driving habits have actually improved... Which is really weird [MENTION=110088]SilverRidgeRunner1[/MENTION] I'm not huge on technical terms haha so do you mean my short term mpg vs long term? Because I've been getting a solid 8 mpg for the past month.

Oh sorry basically its a measurement with in your ECM that is monitored using a scan tool. Short Term Fuel Trim (STFT1 and STFT2) is the computer's immediate response to adjust the air/fuel ratio. In positive corrections, fuel is added to adjust for a lean condition, while negative corrections respond to a rich condition. If this is off by a lot it could point u in the direction of your problem

 

[JeepKiller]

Oh sorry basically its a measurement with in your ECM that is monitored using a scan tool. Short Term Fuel Trim (STFT1 and STFT2) is the computer's immediate response to adjust the air/fuel ratio. In positive corrections, fuel is added to adjust for a lean condition, while negative corrections respond to a rich condition. If this is off by a lot it could point u in the direction of your problem

Oh thanks for the clarification, could I have this done at an autozone or does it require a more precise tool?

 

[SilverRidgeRunner1]

It would be something that would require a little more reading power than just pulling a code because u would be driving and monitoring this information live

http://www.amazon.com/gp/product/B00CKFWKWY/ref=ox_sc_sfl_title_2?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

 

[TheDurk]

It would be something that would require a little more reading power than just pulling a code because u would be driving and monitoring this information live

http://www.amazon.com/gp/product/B00CKFWKWY/ref=ox_sc_sfl_title_2?ie=UTF8&psc=1&smid=ATVPDKIKX0DER

It would also be able to tell you if you are in open loop or closed loop, which is another thing you should check. If you are stuck in open loop after warm-up, you will run rich and burn gas.

 

[SilverRidgeRunner1]

It would also be able to tell you if you are in open loop or closed loop, which is another thing you should check. If you are stuck in open loop after warm-up, you will run rich and burn gas.

Knew I forgot something..

 

[amalik]

8? I think even a v12 Lamborghini city mpg is beating you there.