8 mpg City, no mods except tires...something's gotta be off
- Thread starter LCbruiser2000
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- #22
unfortunately i need the cliff's notes to DIY car repairs...
so in the mean time, can i trust that the guys at Firestone can check all that stuff out for me -- the o2 sensors/ thermostat to see if they are working properly??
I'll see if i can find the post somewhere regarding the thermostat. It's a good read. As far as the diy, you can look in the fsm for the 2004, in the faq section on where the thermostat is and how to remove it. i believe it also tells you how to check it. i think. i'll find the post later. i'm prepping dinner now.
Ok..... i'm waiting for food to cook now.. I re-read the post that i'm linking here, and i realize that perhaps the symptoms this person had are not the same as yours, but it's also worth noting since we all own a toyota. Perhaps this will be of help to the OP and perhaps someone else here. It's worth a try.
Fuel Mileage - Toyota FJ Cruiser Forum
Fuel Mileage - Toyota FJ Cruiser Forum
- Thread starter
- #25
"With the fix in hand it was time to visit Toyota to discuss my displeasure with them. Toyota did allude to a possible known issue with thermostats, but would not confirm their statement. Therefore I suggest anyone who is experiencing poor fuel mileage replace their thermostat. The cost is 60 dollars, 1 gallon of pink antifreeze and an hour of work. You could possibly regain the new truck mileage you’ve been missing since 40 thousand miles. By the way if you look up the recommended replacement term for thermostats its 2 years with a coolant flush.
"
out of that whole post at FJ forum, this seems like the thing to do!
"
out of that whole post at FJ forum, this seems like the thing to do!
Isn't that an item replaced on the 90k pm?
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- Sent from a very small supercomputer.
- Thread starter
- #27
sure is, thermo and the thermo gasket are on the 90k list...
problem is, my mileage is at 63k.....i've done a ton of work to the truck maintenance wise -- probably even before it's due....
i'm just gonna see what happens in december when i take it in.
it's only another 5 weeks - and hope for the best!
The OP implied a change in mileage after new tires and with a creaking noise. The BFG AT in that size are heavy tires (just under 60 pounds each) and if those were a change from the lighter and smaller OEM then the gas mileage difference may be noticeable in the city. Tire weight (rotating mass) and tire rolling resistance both affect gas mileage. The new creaking sound may be coincidental or it may be related. Any other work done with the tire change: brakes, parking brake, etc. that may now be sticking/creaking? Don’t know where you are but winter gas comes on line in the fall and engines don’t seem to run as well on it. Miles per tank or miles per half tank is really not useful for checking gas mileage. I would use that only for sort of grossly keeping track. If you think you're having a gas usage problem, it's probably worth calculating actual mpg for a couple of fill-ups and then checking again after any repairs/maintenance.
Well, if you've got an Android smart phone, get the bluetooth OBDII adapter (~$45), download the Torque app ($0), and go to town logging your coolant temp. You'll find out real quick how well your thermostat is working...
just cruisin around the island....
for $70 I am hoping some one will give it a try!!! But no high hopes.
It sound like it plugs in inline with the intake air temp sensor (IAT) and thereby messes with mixture control. Hot air being less dense then cool air. So I don't think its a true 'chip' that is changing all parameters.
Hadn't heard any of that stuff about the tstat before, interesting. I will agree that 02 sensors can affect fuel mileage long before they throw a code, but it isn't a guaranteed fix. I average 13mpg with no running boards or sliders, an ARB bumper and 305s. It just depends on your particular truck. Some are pigs, some aren't.
That's why products like the tornado still get sold.
That's why products like the tornado still get sold.
Wow, that was very enlightening. When you first posted "check the t-stat" I was thinking he should check the muffler bearings too while he's at it but I gotta admit I learned something new there. Never would've thought about the warm up mode expending extra fuel etc. It's definitely sound logic. Good find!
ETA:
Also as a follow up, 1999 here with good fresh O2 sensors at 200,000 miles, 285/75r16's and still in the 14-15.x range on the highway. I don't have more than a few little stints in city driving conditions anymore and don't really plan to!
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what about resetting the ECU to see if that changes anything? wouldn't it be possible that after resetting, it might throw a code that isn't showing up in its current state? i also thought the ECU "remembers" your driving style and makes adjustments to engine performance based on your average driving over a certain period of time/distance. perhaps this rig was driven like a race car in the past and it just wants to dump fuel every time you drive it? i'm just guessing here...but under 65k it shouldn't have any issues unless its something related to sitting around for a while, 'cuz that's some low mileage.