Recently I have been tracking my mileage on my 2003 TL Type-S with each tank of gas, and it was getting around 16 miles per gallon on average with regular gas, so a friend of mine offered a suggestion to try Premium gas on it. But after a tankful, it got 15 mpg!

The car has new tires, only about 97,000 miles and drives mostly city driving, but occasionally has some freeway miles...

Would there be anything that I need to do to improve my mileage? Do I need a tuneup?

 

stop running a type S on low octane gas--91 or higher--thats it

Seafoam it to get that crud buildup off the valves and cylinders from crud gas

replace the spark plugs--its time, use NGK Iridium IX ....not some cheapo plugs that will not work in the tl--a month later you will be changing them again

 

Oye, supposed to be using premium from the get go!!!

SEAFOAM!

01tl4tl will tell you more!

 

I'm trying Techron Fuel system Cleaner 12oz...
The car has more pep!
I'm getting some pretty bad mileage right now...
370-barley-400 KM a tank... (not pushing it to extreme empty though) - mind you its running rich
I cant find the 20oz size for ~70 L tanks - I think im going to fill up with Chevron 94 (the best cleaner gas i can get) and add the 12oz Techron Fuel system cleaner as well.
Kind of initial thoughts are less ticking/clicking - more power as well!!!
Knock on wood that it gets even better and goes away completely!
The gas station i usually fill up is 6-10 cents cheaper (co-op) but im not sure how many cleaning additives are in it, maby she doesn't like the lower grade 91... What would you thing of adding a small/half amount of Techron every 2nd fill up - it is the same stuff as in Chevron gas... right?

 

Did you check the air pressure in those new tires? Air filter clean?

 

Awesome! Any priority? If I am trying to sell it, is it worth sparkplugs?

Do I need to run seafoam AND fuel cleaners? Is there a major benefit to changing out the air filter to something more expensive or stick with the stock filters?

Thanks so much guys!

 

im getting pretty bad gas mileage too.. im only getting BARELY 200 from a full tank of gas to empty. that's pretty bad. i've recently reinstalled my cold air intake, cleaned my intake/throttle body, resetted the ecu, and checked my tire pressures. why am i still getting poor gas mileage? could it be my fuel lines? i looked under the car and realized one of the fuel lines were hanging pretty low, could that be a sign?

 

I think you're seeing the E-brake line.

 

I noticed those lines too one day...
There's one on each side, the fuel line is metal under the car...
The black lines go to the rear breaks...

I was worried to as I usually scrape on speed bumps if not going 0...

I exit my school parking lot going straight out then turn, as its a downhill exit, cant make it with a sharp corner...

 

DANG...you guys only doing city driving? Have a real lead foot on the gas? My 02 TL-S has over 167K miles on it and it still averages 24 MPG.

Yeah...using the correct octane would help. LOL.

 

dont drive with a lead foot
use premium 91+ (even though it wont improve fuel economy)
make sure car is up to date on service
reduce weight in car (take out excess objects)

i started getting better gas mileage after my 105k service which i did when i got the car at 98k. currently im getting about 16-17 city and 27-30 highway.

 

yeah.. im only doing city driving.. and barely any freeway driving. and i drive as slow as possible since im slammed but i still get crappy gas mileage. but i do smell gas sometimes from stop to stop.. i know it's something to do with my fuel lines. any other ideas?

 

Ouch...city driving is a killer on gas mileage. Take your car out for a long spin on the freeway. Try to do like a 100+ mile trip and then see if your car's mileage improves. If it's still shitty...then time to take it in to get looked at.

Yeah...smelling gas isn't a good thing. Might want to take it in for that. Safety issue.

 

seafoam is better than techroline and 1 can will make a huge differance--techroline=3 cans

chevron/texaco gas contains a MAITENANCE does - meaning over several tanks it will slowly clean crud away for you

a bottle of it is concentrated but needs to run at max dose allowed to do a super cleaning in 1 shot

that big tire chain store in Canada carries seafoam

If you are trying to sell the car.. it will make it run way better for 10 dollars and 30 minutes of your day- vs $50 for new plugs and an hour of your time bent over the engine

Vac leaks after cai install and city driving are bad for the TL
Dont lug the engine!--2500-3000 rpm shifts with light throttle are good for mileage
Engine needs to be on the torque band to make it move forward with least energy

short-under 10 mile drives are really bad for mileage--take the car on a 45 minute freeway cruise once a month to dry out oils, charge battery and clean off the plugs

 

the TL prefers Tier 1 gas- which has more cleaner- up to twice the govt minimum required-
tier 2 has min amount
there is a list online of brands but most major names are t1

Type S cars have higher compression than type P,, 11 or 11.5 to 1 iirc, thats a big number!
carbon buildup on the piston tops increases compression and causes pinging, predetonation, run on,,all bad things for the car

treat the tl well and it will reward you- try going cheap and it will show

 

you should NOT smell gas!!
find the fuel leak and mileage may improve~

sniff under the hood with engine running, and off
take it to a shop if you cant find leak
look at gas cap, parts store can pressure test and visual the seal oring for cracks

 

I get pretty bad mileage in the city too. Our cars are just bad for the city. If you care that much, get a 4 cylinder engine and a smaller car for sure. I was actually thinking about it but a much slower car = HELL NO.

I get about 250 miles on a tank now in the city. Seafoamed, new plugs, clean air filter, fresh Mobil 1 syn oil and oil filter and always 93 gas. But I do some serious city driving since I live in the downtown Manhattan. My foot is on the brake like 10x more than the gas. It sucks.

But I did get about 29 mpg all highway before I did my plugs and everything which is pretty good. Haven't had a chance to do another test. But I was driving about 70-75 mph with a foot as light as a feather.

 

Where I live has the highest seinor % anywhere...
I don't "rip" around in my car - im not that kid.
At this age you don't have the experience to drive fast.
No winter, verrrry mild weather - lots of rain, lots and lots of rain.
I do climb a 45* hill every day to school - its like 800-1000 meter climb (idk like 200-300 yards snaking...)


I lighten up on the throttle before the car shifts as well (i know when she's shifting "spidey sense").

Um I have 2 questions...
when i drive up the steep hill every day, is it better to go into d5 (witch will shift into 3rd halfway up while climbing) or stay in second the entire time... easier on clutch packs?

I have 5 min of driving over speed bumps at slow speed to get to the national training center sport center, is it better to go into SS and stay in second the entire time or go D5.

 

A saturated charcoal cannister might be the source of the gas smell.

 

look down, see your foot, jack rabbit starts and taching it out kills the gas millage.

 

leave it in D5- let the car outdrive you
avoid SS use as it will drop mileage!!

DO NOT let up on the gas as it prepares to shift
Its calculations are based on where the throttle was


Good Call on the cannister,,, Total'd always has the answer!!!!
If you fill the tank to past the auto shutoff of the pump- chances are very good that fuel will get to the charcoal can which is supposed to only hold fuel vapors when car parks and ~things happen with heat and fuel~

someone else had that recently- had often `over-topped` off the tank,,,
changed part and smell gone- car seems to run better,,,maybe thats from not worrying about fire at your feet constantly...

 

i gotta admit that i do the same thing. ever since my old tranny started slipping, it became a bad habit. i really only do it between 2nd & 3rd gears. i don't totally let up, but i ease back on it...just scared to ever see that gear slip again

same here. 170ish miles now on my 03 .. do a mix of mostly highway & some city
get from 24-27 on average, and I typically do around 80mph on i-state

 

lol.. like i said.. i'm slammed and i don't even do jack rabbit starts. if anything, my starts are slow as hell.. everyone behind me changes lanes as i never pass above 2k rpms.

 

thats NOT helping your mileage~
as I tried to explain about torque and rpm--let the TL get moving!!
2500-3000 rpm is better than lugging/going very slowly... the engine below 2000

 

I went through this about a year ago. I was getting 14-16 in the city. I couldn't understand why. After finally looking into a few things, I settled on the fact that the o2 sensors (one off of the engine and one off of the cat converter) needed replacing. They look like incased spark plugs.

After reconnecting the battery and the computer resetting, gas mileage jumped sky high! The worst I have gotten since then is 19(the week I smoked a g35 sedan and a Genesis coupe). I have gotten as high as 23 in the city. My car is lowered and is waxed all the time so that helps some too. My last road trip I got 34.66 on the road at 75mph!

 

That is some pretty nice mileage. But how much did it cost to replace your o2 sensors?

 

the front is most likely to wear out,, use denso - plug and play unit, is the oe supplier too, can buy at parts stores eveerywhere

how many miles on the car? use 91 octane always? name brand gas?

you can do an electrical meter test on the sensors to see if the are giving good feedback to the ecu

seafoam will clean O2 sensors! and cat!!