04acuratlinstl

I just purchased a 2004 TL with 50xxx. Previous owner said he used unleaded to midgrade gas ive been using premium gas but ive been getting 14.8 MPG!!!!! what can i do to improve it??
No modifications are done to the vehicle, its in factory condition mint!

Costco

and you still bought the car?

The ECU probably retarded timing to compensate for the lower grade gas and he's been driving around like that forever. Disconnect the battery, leave it for 10-15 minutes, connect the battery again and drive normally. You should notice an increase in performance and economy.

fsttyms1

Is that all city?

LoveMyTL-S

After reseting the ECU, give it some time to learn or adjust to the new readings and your driving style. Hope that is all that is wrong. Probably wouldn't hurt to Seafoam your TL as well to clean it up:

https://acurazine.com/forums/3g-tl-2004-2008-93/107-diy-seafoam-3rd-gen-tl-06-5at-specifically-638069/

Welcome to AZ

04acuratlinstl

I spoke with the dealer today and they said resetting the ECU will not do anything other than that he didnt have an answer for me....... I put some Lucas fuel injector cleaner in it and switched gas stations we'll see if that helps.. thanks for your input all suggestions welcome

Jaco

iTrader: (1)

Might want to check the air filter to see if its clogged if the car has not been serviced.

daneo

also your o2 sensors. They don't always throw a code when they are messing up. I've had this happen to me on two different cars.

dwb993

iTrader: (13)

1) Change all filters/lubricants, etc
2) Seafoam according to the instructions in the thread listed above
3) Reset the ECU per the instructions above
4) Don't drive it like you stole it

My 06 with 43K got 31mpg on a 150 mile trip last week, according to the trip computer. I haven't kept records and done the math to verify, but several on AZ have confirmed the accuracy of our trip computers.

Congrats on the new ride and welcome to AZ!

04acuratlinstl

The air filter is clean, the oil change has been done. used lucas fuel injector cleaner today and will see if that helps, according to the dealer resetting the ECU will not do anything... and I drive normal and not hard. dont know what else to do....

dwb993

iTrader: (13)

forgot to mention tire pressure---book says 32psi all around. I use 38psi front/35psi rear--for long trips, I pump up the fronts to 40psi.

fsttyms1

I find it hard to believe that its 14.8 city or hwy. These cars are not the best cars for city mileage, but all HWY many see over 30.

LoveMyTL-S

Right now I'm getting 23/24 MPG with mixed city/hwy. As I get on both for my commute to work and I'm due to change my air filter.

Bearcat94

You were good all the way up number 4 .... lol.

An easy right foot is one way to improve mileage.

OP - Reset teh ECU. Dealer says it won't help, fine. Won't hurt either and may have a quicker effect on adjusting to a clean air filter, new driving style, etc. OR you can just wait it out a few weeks for the ECU to adjust on its own.

Also, Seafoam through the intake, not just an injector cleaner in the gas tank. Plugs might help. You're really not due yet, but pretty close on time (6 years). NGK Iridium if you do.

BTW - as asked: City or Highway? We get 18 - 20 mostly City, but WAY more on the highway.

04acuratlinstl

Thanks all i will try these new tricks.... also its suppose to be a 17 gallon tank but i dont it is... cuz it cost me $31 to fill up but i think it has a small tank... or am I wrong?

csmeance

its 17 gallons, but you have reserve space and also fume area's. You'll fill up with 12-14 gallons depending on how much you drive with the line on.

Jackass

All highway taking it easy can get really good numbers.

This was pure highway running at the speed limit of 70mph and 65mph. Oh how I wish it was always that nice. The next morning my drive to work had dropped it back to 31.

How are you determining you are getting such bad mileage? Are you actually doing the math? Or just going off the display? I have yet to put more than 14 gallons in during a fill-up. I just have no interest in finding out how low I can go. I hit about 1/8 of a tank and fill up. Usually ends up being around 13 gallons which usually gets me around 350-400 miles.

Bearcat94

There is a very good thread in the 3G garage on this.


Like aj says, there is a reserve. Basically when your low fuel light comes on, you have around 3 - 4 gallons left and your RANGE in the MID will be ~25 miles. When the RANGE in the MID hits 0, you have about 3 gallons left and can drive ~60 - 80 miles (depending on conditions, etc).

Normal fill up with the low fuel light on and the MID RANGE above 0 should be ~13.x gallons.

LaCostaRacer

You'll want to do a search on gas mileage. My guess is your average MPH is pretty low (like below 25 mph) and you're stopped at either a lot of lights, idling the car for long periods of time, or simply in stop & go traffic. There's a thread in this forum that correlates average MPH with MPG. My usual MPG is 19-20 and my average speed is just 28MPH so you have a baseline on what to expect for suburban driving with an fast driving style.