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Low gas mileage; paranoid or justified?

16210 Views 99 Replies 42 Participants Last post by  wildbill23c
Hey everbody, I've been a guest for about a year but just became a member yesterday. I've come here several times because of issues with my 2012 5.7 flexfuel Crew Max 4wd and I have found this site to be a great resource of information. I've read posts about gas milage and I know the 5.7 is not an economical engine but I'm only getting 8-9 miles city and I have never got better than 15 highway. I drive very conservative no quick take offs and speed limit on highways. No mods, yet, and stock 18" wheels. I've already had to have my computer reset twice because it was misreading the fuel as ethanol(E85). Dealer kept insisting that it was my fault, that I had put in E85 and I would have to pay them $90.00 an hour to drain my tank. Excuse me, but it is a flexfuel engine is it not and besides I do not use E85, period. Thanks to this site I was able discuss that particular problem with some knowledge of the situation. I'm at my wits end with this truck, my dream truck has turned into a nightmare. Any information or suggestions will be appreciated.
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I disconnected the battery to reset the ECU, filled up the tank from a different gas station, took it on a 150 mile mixed speed trip and I still got terrible gas mileage. Looks like I will have to take it into the dealer for a ECU reflash this week. Are people having success with the new release?

Thanks.
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I know that alot of folks get the touneau covers on their tundra, I too have (had) one on my 07.....once I got my gooseneck installed it became more of a pain-in-the-a** so I've left it off and noticed that my milage increased! At first I thought that maybe it's coincidence due to the winter/summer fuel switch but tested that theory for a tank and it turned out to be true, it actually did get better milage withour the cover. and for years I've thought that the cover or camper shell would help milage more cause of aero-dynamics, but I guess not!! I know is just rambling here but it could explain the bad milage(but honesly, I don't even get less than 10MPG in my 07 CM 4x4 while towing my 32' GN horse trailer loaded (GCVW >17500#))
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I disconnected the battery to reset the ECU, filled up the tank from a different gas station, took it on a 150 mile mixed speed trip and I still got terrible gas mileage. Looks like I will have to take it into the dealer for a ECU reflash this week. Are people having success with the new release?

Thanks.
I don't think disconnecting the battery does anything for this issue unfortunately. Would be nice
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You need the new flash that IS out for the 12's and 13's. Go to a good dealer.
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Good news is, just this weekend Toyota came up with a re-flash that should correct the problem. I was the first at my dealership to get it done. Here's hoping it works out.
Thanks for the info stompinstu. I had the dealer install the updated re-flash this afternoon, so hopefully it works.
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I hot rod around town a lot and get 12mpg. there is a DEFINITE issue.
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16.58 highway and 14.3 city. I don't abuse it, but I don't drive like I have a case of eggs on the seat either.
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Alright, got the re-flash to fix the flex fuel issue and an update on the AIP last week and still no reprieve on the gas mileage. I'm still managing 8-9 mpg in town with speed limits around 35 and still a little bit of a rough start when cold. I give up this is my first and last Toyota as soon as I'm no longer upside down its getting traded.
Really, the flash did nothing? Did you get a readout of what alcohol density your truck is running?
well poop

I posted this in another thread:
Ford owners sue, saying EcoBoost engine defective

Too bad it's just the FFVs and not all Tundras. If this was happening to all we'd probably be following/leading the ecoboost owner's in a similar charge.
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I think that's unusually low. Unless he's towing a 8k trailer around the city. I get 15.1mpg city on my 2007 and like 20-21 hwy...

He's getting like hummer h1 gas mileage....
My '10 DC 5.7 4wd got 13 city and 17 hwy. The 12 gets about 1 mpg less.
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Alright, got the re-flash to fix the flex fuel issue and an update on the AIP last week and still no reprieve on the gas mileage. I'm still managing 8-9 mpg in town with speed limits around 35 and still a little bit of a rough start when cold. I give up this is my first and last Toyota as soon as I'm no longer upside down its getting traded.
Same here: got the reflash last week, driven ~100 miles of suburbs with top speed of 40 mph, never above 2K rpm, new tank of gas and still 7.8 mpg avg. in fact, the average continues to decrease as I continue to drive. This is insane fuel consumption for a brand new vehicle. Not thrilled, to say the least.
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I would escalate this problem to Toyota management. They should have a regional exec for issues like this.
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its so sad i have the same issues i have a 2013 rw crew 4x4 and i almost dont even like my truck because it literally gets about 9 mpg...the sticker said 13-17 epa not even close...

I am having an issue with 2 other things on the truck

1. In 2wd with the trac control off the front end is making a clunking loose sound like the thing is gonna fall apart,

2. on the fwy a big sweeping turn the truck sounds like gears are binding at 45 mph through a big sweeper...

i really like my truck but these issues are forcing me to not take her on long trips which i bought the truck for with the crappy gas milage...

Lemon here i come....should i take it o the dealer for the MPG? is this a valid argument i feel like i have been mislead!
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its so sad i have the same issues i have a 2013 rw crew 4x4 and i almost dont even like my truck because it literally gets about 9 mpg...the sticker said 13-17 epa not even close...

I am having an issue with 2 other things on the truck

1. In 2wd with the trac control off the front end is making a clunking loose sound like the thing is gonna fall apart,

2. on the fwy a big sweeping turn the truck sounds like gears are binding at 45 mph through a big sweeper...

i really like my truck but these issues are forcing me to not take her on long trips which i bought the truck for with the crappy gas milage...

Lemon here i come....should i take it o the dealer for the MPG? is this a valid argument i feel like i have been mislead!
How many miles have you driven? Check the lemon laws in your state because they vary. I think we all have legitimate arguments, in fact if anyone knows of a way that we can get a group together and file a formal petition to get Toyotas attention.
its so sad i have the same issues i have a 2013 rw crew 4x4 and i almost dont even like my truck because it literally gets about 9 mpg...the sticker said 13-17 epa not even close...

I am having an issue with 2 other things on the truck

1. In 2wd with the trac control off the front end is making a clunking loose sound like the thing is gonna fall apart,

2. on the fwy a big sweeping turn the truck sounds like gears are binding at 45 mph through a big sweeper...

i really like my truck but these issues are forcing me to not take her on long trips which i bought the truck for with the crappy gas milage...

Lemon here i come....should i take it o the dealer for the MPG? is this a valid argument i feel like i have been mislead!
I'm not sure why you are driving with traction control off, but it sounds as if 4WD is stuck on. I would complain, as something is amiss, and I think it's in your transfer case / differentials.

When you are in 2HI, and make a tight turn, like steering wheel at full lock, does the truck roll freely; or does it feel like it is binding?
Really, the flash did nothing? Did you get a readout of what alcohol density your truck is running?
No. I'm working in the Pacific Northwest right now and they know nothing about the flex fuel engines but I have my 25,000 mile service coming up ill ask for it.
well poop

I posted this in another thread:
Ford owners sue, saying EcoBoost engine defective

Too bad it's just the FFVs and not all Tundras. If this was happening to all we'd probably be following/leading the ecoboost owner's in a similar charge.
Seems like we should still have some legal recourse given the amount of owners that are having this issue. I'm going to check with an attorney and see if we have a leg to stand on
For you FFV guys that are suffering from low mileage, how does you tail pipe look? Is it sooty?
No soot. Lots of vapor from condensation though
Has any FFV owner with the poor mileage problem had an oil analysis done? If so, can you post your results?
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