Poor Fuel Economy (1 Viewer)

Joined
May 28, 2016
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Cambridge, MA
I'm seeing significantly worse gas mileage in my new-to-me '07 LX than I did in my '03 LC with the exact same wheels and tires. Thinking about swapping out the air filter, fuel filter, spark plugs as preventative maintenance. Also running some injector cleaner through the tank. Any suggestions?

Truck runs and drives great but does idle high on cold starts (~1500 rpm). Normal idle ~650rpm once the truck warms up.
 
Joined
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Seeing 8.5mpg in city driving for the LX vs 12mpg in the LC.

On the highway getting 14 - 15 mpg in LX vs 17 - 18 mpg in LC
 
Joined
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DC
Highway mileage you're getting Prius numbers compare to what most of us get here, city mileage is rather low. Do a full tune up if you haven't, and check for dragging brakes. Also, in the winter, gas companies add additives that gives us poorer mileage than summer blend.
 
Joined
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Truck runs and drives great but does idle high on cold starts (~1500 rpm). Normal idle ~650rpm once the truck warms up.
Your 07 like mine (06) has VVTi, we have the same cold start idle at around 1500rpm (bec of SAIS) and in the same rpm when it is in its optimal temp. I went 306 miles for a 21 gallon full tank (14.5 mpg). The only thing I changed from factory specs are the 275/70R18 AT tires running @ 32psi with 1.25” BORA alum wheel spacers. I use the truck around 80% at 45mph zones only and top speed is just 65mph freeway speeds.
 
Joined
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I generally drive with a very light foot.
Your 07 like mine (06) has VVTi, we have the same cold start idle at around 1500rpm (bec of SAIS) and in the same rpm when it is in its optimal temp. I went 306 miles for a 21 gallon full tank (14.5 mpg). The only thing I changed from factory specs are the 275/70R18 AT tires running @ 32psi with 1.25” BORA alum wheel spacers. I use the truck around 80% at 45mph zones only and top speed is just 65mph freeway speeds.

Interesting! I was not aware of the air injection that was added along with variable valve timing.
 

gregnash

Anal Retentive Analyst
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Interesting. My 98 has been averaging about 11mpg with mixed city and highway (70/30 or 80/20) so I figured that she was not gonna get great mileage. I am going through and doing a lot of refreshing as she was a driveway ornament for the most part of the PO it seems like.

Running a 1.5" lift, 285/75r16s in load E with 38psi front and 40psi rear. Sliders are the only "armor" to speak of at this point, no aftermarket bumpers, roof rack, etc. Plugs looked in decent shape for me, air filter was clean, so now it is just going through and chasing different things while I fix other items. Not a huge deal to me but still would like to avg. closer to 13-14 if possible.
 
Joined
Jan 3, 2014
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Kentucky
 
I get 14 between both in my 98 but I have to keep it to the speed limit. 65 + will lower that and if I'm hauling anything (2000+ lbs) I'm around 10 mpg at 65/70. You have higher horsepower that I do.
 
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Las Vegas NV
I generally drive with a very light foot.



Interesting! I was not aware of the air injection that was added along with variable valve timing.
Trust me I’m the guy you’d curse at the road for driving slow even my 11yo daughter asks why everyone has overtaken us, I just say look on the bright side we get to spend time more Lol. I’m actually on the fence for a regear or one of those 12-hole injectors upgrade it’s actually perfect for how I drive -just partially opened throttle.
 
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^^^^^^ Look at the gas you could buy with the cost of that.
Yeah that makes sense. I got a parts quote from nitrogears for a regear kit its around $1500 parts only and labor is roughly the same as the parts.. I think the regear would be when I have the f/r arb bars and sliders are installed in a few years from now maybe. The 12-hole injectors is arouns $150 for the whole set.
 

MongooseGA

Learns things the hard way
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Trust me I’m the guy you’d curse at the road for driving slow even my 11yo daughter asks why everyone has overtaken us, I just say look on the bright side we get to spend time more Lol. I’m actually on the fence for a regear or one of those 12-hole injectors upgrade it’s actually perfect for how I drive -just partially opened throttle.
As long as you're not in the left lane, you're all good!

Y'all are going to think I'm a magician...

20200124_121714.jpg
 
Joined
Nov 4, 2007
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Colorado
 
 
So many things effect MPG. In a new engine with 0 miles number one is driving style. Number two is allowing engine to idle excessively (more than 5 minutes or often for even less time)..

Sure you use gas without putting on miles when idling, which lower MPG reading. But the reason Toyota states do not allowing engine idle excessively is "CATs". Running on the HWY at 70 MPH is ideal for CATs. Idling excessively or sitting in slow moving heavy traffic can clog CATS.

After engine all tuned up which may include a new Fuel pressure regulator. You still get poor MPG of 8.5. Have CAT back pressure tested.
 
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Joined
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Mobile, AL
 
“But the reason Toyota sates do not allowing engine idle excessively is "CATs"“

Really? Wow, I purposely let truck idle instead of cranking so much when getting out of truck while working in woods.
 
Joined
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I use 5 minutes as rule of thumb, Toyota states 20 minutes. But yes really!
Idling also builds up moisture in exhaust systems, caused rust issues.

056.JPG
 
Joined
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Read a thread somewhere on MUD about fuel injection service. Unable to find it now but the premise was poor fuel economy after the fuel injection cleaning service.

It could be that your new 100 consumes fuel faster due to more clean lines or however the injection system works.

I recently had the fuel injection service done but haven't been monitoring the MPG. I do however believe the engine runs better and seems quicker which would make sense for more fuel consumption.

Edit : Thread location Gas mileage decrease after injector cleaning...
 
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MongooseGA

Learns things the hard way
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Negative. This was actually over a net incline, going from the suburbs of Atlanta into the foothills of the Tennessee mountains outside of Chattanooga.

The big thing here was keeping speed between 60-65. We had a Jeep in our group who had to keep speed down because Jeep. I was amazed though, because the truck was carrying an easy extra 500lbs of gear in it.
 

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