I'm sorry but I have to ask about my MPG

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G

GranolaJoe

10 Year 15 Year
Joined
Jul 15, 2010
Threads
20
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115
Location
Oklahoma
My apologies in advance for asking about MPG's. The sad thing is that I've read many of the MPG threads here and still feel I need to ask about my situation. Don't hate me.:frown:
I have had my 07 LC for almost a month now. Less than a week after I bought it, I put on 285/65/18 NTG's (the only thing I've done thus far that should affect mileage). It now has 92k and it's in today for a 90k service. It's an independent shop and they are doing the all the belts, arms, and pulleys, thermostat and rings, water pumps and rings. They have already checked the MAF and the throttle body and both look good.
I took a 1200 mile trip in it last week and my MPG range was 9-12. Even with the bigger tires, doesn't that sound low? Is there anything they should check while they are in there? They have already checked fuel mixtures and just said it was fine.
 
Did you adjust for bigger tires in your mpg calculation? Usually with 33s you multiple how far you traveled by 1.10 then divide by number of gallons.

What were you hauling, what was on the roof? How many people were with you? Are the tires properly inflated? The list goes on and on to the break of dawn. How much armor do you have?

That seems really low for larger tires only with a 5 speed tranny.
 
Yeah, gotcha, good questions.
Carrying 4 people for the 600 miles there and gaining altitude (about 8000 feet over 600 miles) and got 8.9-10.2. On the way back, I was carrying just 2 total and obviously going downhill and was around 12. Drove 75 on interstates and 65-70 on 2 lane highways. I have no armor yet and was carrying 1 set of skis on top. Tires are at 38psi. The third row seats are sitting in the garage.
 
more like 6% I think for 33s.

So, yes that's very low. On the highway our 03 does 17 or 18 on the high side, loaded with camping gear and people. More like 12 to 14 in town.

One reported cause of low mileage is the 02 sensors but since it's an 07 that's not highly likely, but then it's pretty easy to check those I think, so maybe worth looking it when you run out of other more obvious possible causes.
 
if you are going by the Trip info, NAVI manual says you have to re calibrate the NAVI when you change the tires...
 
What they said. You need to adjust for your larger circumference tires, because your 100 is not doing so automagically. Your indicated speed is going to be off too (reading slower than actual).

See this post for my experience and calculations.
 
Thoughts:

  • With 295/70R18's my GPS-adjusted factor is around 1.12.
  • I'm getting around 13 in mixed driving.
  • My MPG always goes noticeably up when driving hills. The LC has a complete fuel cut when the RPM's are above 1150 and the throttle is closed. So while you're burning more going up, you burn zero coming down. The net effect for me has always been a positive in rolling terrain. If you feather the gas on the downhill (or otherwise when decelerating) the benefits go out the window.
  • I run around 44 PSIG.
  • I drive around 65-70 on the highway and see around 15 (GPS-corrected)
  • Based upon the above, I'd say there's something wrong. Either you have bad O2's, low tire pressure, a vacuum leak, or something causing a mileage hit. Even on dirt I've never seen single-digit MPG's.
 
i get low gas mileage as well in my '00
probably in the same area as joe with 285/75/16's.

maybe i need to change my 02's and clean the maf???

e9999 said:
more like 6% I think for 33s.

So, yes that's very low. On the highway our 03 does 17 or 18 on the high side, loaded with camping gear and people. More like 12 to 14 in town.

One reported cause of low mileage is the 02 sensors but since it's an 07 that's not highly likely, but then it's pretty easy to check those I think, so maybe worth looking it when you run out of other more obvious possible causes.
Click to expand...
 
uzj100 said:
Did you adjust for bigger tires in your mpg calculation? Usually with 33s you multiple how far you traveled by 1.10 then divide by number of gallons.
Click to expand...

10% adjustment is a bit aggressive. The circumferential difference is more like 5% from a ~31.2" tire to a 32.6" tire.

I have 305/60/18s on my '06 - same driveline and exact overall diameter to your tires. On a trip from San Diego to Sacramento and back, I averaged ~13.8 mpg with pretty aggressive 75-80mph driving. Inflation pressure ~35psi.

I'd say the ski and rack are a big part of your low mpg. Back when I had my '05 4running, I noticed a big 2-3 mpg hit whenever we travels with a ski rack. So much so that I traveled with them in the truck whenever we had the space.
 
My money is on the skis. I kept my snowboard rack on for the whole season last year and noticed a consistent 3 MPG decrease and then went right back up once it was removed. I have also noticed that my 2000 LC get the best mpg at 2400 rpm where anywhere above that it significantly starts to drop off. On the highway, for my 4 speed, this translates to about 70mph.
 
SHAGGY101 said:
I kept my snowboard rack on for the whole season last year and noticed a consistent 3 MPG decrease and then went right back up once it was removed.
Click to expand...


:eek: Wow! I also try to not get above 75/2500 myself when cruising.
 
Sunday I drove from Las Vegas to Reno.

From LV to Beatty I drove 70-73MPH into a head wind, we Filled up and calculated our GPS corrected mileage. We got 12MPG

From Beatty to Reno we drove 65MPH max and lost the head wind, we got 16.5 MPG.

Based on past driving I can tell you any speed over 65MPH will kill your mileage. I can also tell you we would never have gotten that kind of MPG when we had the Toyo Open Country MT's on the truck. The heavier tire combined with an aggressive tread just killed our mileage.
 
with same size tires....heavy BIOR front and rear bumpers, winch, loaded with gear......and adjusted in UltraGuage for tires....I typically get 12-13 around town and 15 on highway if I stay below 2300 RPMS....if I stay below 2000 RPMS I can see an improvement of at least 1mpg...

something to remember....those tires are very aggressive and have a high rolling resistance. the other is they weigh about 90lbs each mounted...that is over double the oem tires so every time you start or stop it kills mileage.

Keep it around 60-65mph max....good tire pressure...no head wind...would think you would get around 15-16 on flat highway without a lot of hills. If you drove it with flow of traffic near 70-75mph that is about right then as they get thirsty at higher speeds and rpms.
 
I get 13-14, lifted and 285s
 
i'm completely stock besides the bigger tires and run an average city/hwy of 11.8mpg on the last fill. you're still doing better than me with all your additions ;/
 
LCbruiser2000 said:
i'm completely stock besides the bigger tires and run an average city/hwy of 11.8mpg on the last fill. you're still doing better than me with all your additions ;/
Click to expand...

15.2 on the hwy @ 70 mph and 12.8 or so around town with stock size Toyo OC's on my '00 100. Stuff on the rack/top can act like a sail though. I run synthetics and all maintenance has been done.
 
I am betting on your actual reported speed being 78-80 (since you said 75) and the adjustment (6%) putting you over 82. The truck will ride at that speed comfortably (especially an 07 with the tranny and HP improvements) but will suck gas like a cruise liner. My few long trip with the 2000 all got uncorrected 15+ and my local average is an uncorrected 10.5. Stuff on the roof will hurt also. Any chance you got a batch of e85 "Gas"`?
 
If you have a GPS, sync up the trip odometers on your GPS and on your truck and figure out what percentage your odometer is off. It may only be a few more percentage points, but at least you will have a more accurate reading when doing math at the pump. I have 295/75-16s and mine is 8.75% off.
 
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