So i have a 02 tl-s, and lately i'v been noticing it's eating a lot of gas. It's been getting just about the same mileage as my friends 4.7 V8 toyota tundra.
So i took it to a shop and had some tests ran on it, came back with no problems, in fact the mechanic told me the settings (for my 131k miles) were exactly like they were when it first came out of the dealership. Problem is the tests were done by a computer, and not actual physical inspections.
Any idea's on what it could be? or what i can check out myself?
Thanks in advance!

 

check the throttle body butterfly valve. at 131k miles it should have lots of carbon build up.
clean that with some carb cleaner.

run some seafoam.
have you changed the spark plugs?

 

i was thinking that it could be that too, but could that really cause me to have 250-300 miles on a tank?

 

also, what's seafoam? and yes i changed the spark plugs like 700 miles ago. put those NGK iraniums or whatever you call it lol.

 

cleaning the throttle body is part of a "tune up" per se.
Clean it, because I'm sure its filthy.

Seafoam is a cleaning agent that you can pick up locally at wlmart or an autoparts store.
you run it through your gas tank and pcv.

It will clean and make your car run in tiptop shape.

I dont know the instructions on seafoaming...try searching for a DIY on acurazine.
also, if 04tl01 chimes in he can help you even further.

 

make sure you dont have any collapsed calipers, if all of the above suggested methods dont work for you

 

try 200 here lol, but anyways how does the tranny feel...

 

Air filter condition? Tire pressures good?

 

the basics

 

i get around 200-220miles per tank. but most of my driving is city driving.

over the summer when i only joy rode the car I was getting 350+ mpT and that was all highway pretty much

 

I think most everything has been covered

Inspect the basic parts--air filter is a big offender,
air pressure in tires is another
seafoam the gas tank, 1 can to just under half tank, and we use the master vac port- not the pcv to get cleaner into the engine intake manifold
Always run quality tier 1 gas,,91 octane or higher

You clean the TB plate by removing the air tube from air filter to engine for access.
search my name and `cleaning` should produce plenty of diy help

tire alignment makes huge mileage differance-- if the car is trying to rip itself in half or compact itself as it goes down the road~
look at tire wear for indication of low pressure or alignment issue
NOTE most cars need more air than the 32 psi stock tires suggest
Look at max cold weight and pressure
subtract car actual weight and you get about 80 percent on most tires
lower the tire pressure 20 percent from max and see how that goes
A lot of low profile tires with 50 psi max need 40-42 cold to run right
that 2 mpg there!!!
cars running 32 may find 36 ideal and gain freeway miles

Not much you can do in town but drive like an egg is under the throttle and brakes,
be gentle, brake early-- when a red light is ahead, let the car coast-in gear- towards the stop
Light goes green and you are still moving- excellent!- getting 3600 lbs going on inertial momentum vs accelleration of stopped object...

nice new sticky tires lower mileage,, low pressure tires lose mileage

 

Its due for a valve adjustment, and EGR port cleaning while the manifold is off
Both affect engine running, power output, and mileage

 

stock sized tires call for roughly 32, but indeed really need about 36-38...

 

Thanks 01TL4tl.

master vac port not pcv - check.

 

reminder and for noobs
The master vac port is located at TB to manifold-(remove top engine plastic cover)
Its the only finger sized hose with a squeeze to release type clamp on it
When hose removed a metal nipple extends from baseplate--thats the right one!
pulls 20 plus inches vac- so if using seafoam liquid-pour it into a clear container and keep hose 1 inch above fluid level
it creates a tornado in the bottle!
If using spray version-Deep Creep- keep 1 inch away from tube and spray--will make tornado there too
Dont forget the TB air plate- remove air tube to air filter for access
Lube throttle return springs on TB

 

32 for stock tires is to maximize comfort, but is not the best pressure for the tire to provide best mileage

is anyone still running the micky slips that came on the TL?
go aftermarket for much better choices at less cost

 

youre shitting me? youre lucky to be getting that much. im suffering from poor gas mileage .. i only get barely over 200 for a full tank. after 40 miles i am almost halfway to half tank. at half, i get around 100 miles.. you get the idea..

i do mostly city driving, but i do drive on the freeway at times but still.. i think it has something to do with a fried ecu or maybe i need a new o2 sensor. fried ecu cus my buddy didn't bolt in the alternator plug in correctly.. thus it was basically sparking everytime i started the engine. and a new o2 sensor since the guy at the exhaust shop didnt use a stand to cut off my midmuffler, so it sent my exhaust hanging down, which ripped out the wires from the o2 sensor plug..

i cleaned my throttle body, checked tire pressures (upped it to 34psi), adjusted throttle cable (more sensitive now so i wont have a heavy foot), drive slow. nada works.

 

The bottom line is, a 02-03 TL-S just DOES NOT get good fuel mileage.
It is not an economy car by any means.
OK on the highway, but surprisingly bad around town.
16 mpg around town with a pretty light foot is probably average.
Less mpg than that if you enjoy much of its power often.

 

what a bunch of shit being thrown out on this thread the car will get low 20's in city if properly tune-up, using premium gas and driving like a civil human being.

Jack rabbit starts, reving up the engine and trying to treat the car like it's a race car isn't the way to go or a CAI system either. I consitantly get 450-500 mile out of a tank of gas, 350-425 if only city driving.

 

What's your driving style like?

 

I would not say a bunch of shit being thrown around is accurate. First off he didn't say if that was all hwy or mix or city. And if you do a search on this heavily discussed topic that his mileage isn't that far out of the norm.

Also I get shot the same among of miles out of my expedition as I do my TL. Difference being I'm sticking roughly 14 gallons omit as opposed to 24 to 27 gallons..

 

dont adjust the throttle cables to be tight!
they need some slack at idle, and full throttle with pedal should move TB air plate to level position
Tight cable prevents it from going to idle correctly

a bad ecu- dont think the car would run!
a bad O2- seen lots of those going out recently-~150kmiles--yeah its ready.
tore the wire out!! and you are wondering why its getting bad mileage???

 

yeah.. my buddy is suggesting that i borrow another tl-s' ecu and see if that will correct the problem.. cus he says if my ecu is fried.. then that means my computer won't read any codes so i wouldn't know if it was really my o2 sensor or not. i'm just gonna invest in a denso o2 sensor as a replacement and see if that fixes the problem.

thanks for your detailed help, 01tl4tl

 

thats what i get with a heavy foot though, but as said not an ecnomy car to begin with, so it has some weight to move around before it ever gets going

even mid 20's possible (i was getting like 23-24 when i first got my car, then it went downhill from there )

 

most car manufactures seem to calculate their fuel capacity needed by that mileage roughly

 

Alright, just to answer some questions i DO drive my tl-s pretty rough, but when i first bought it i drove it even worse, i went from a 05 escalade (which barely moves) to this and the increase in power was quite enjoyable so i drove it very roughly but i was getting better mpg then i do now, and i drive it fairly light now, i even filled up my tank and drove it from portland or to seattle wa, and i couldnt make it there on a half tank, compared to when i first bought it i made it back and forth on a little more then a half tank. Also, i do about a 50/50 highway and city driving.

Another thing, i recently had a idle rpm issue. I took it to my mechanic buddy and he told me it was the ICU (idle control unit) and he was able to fix the problem (which was when idle and in gear the car would lose rpm and "attempt" to die) but after he did fix it, i have had roughly 100 rpm less then a tl-s should have on idle, could this effect it?
Oh and if you're wondering how he did it, on the unit itself is two screws which are not meant to be unscrewed, so he cut a line in each one, unscrewed it and twisted the wheel inside, put it back on and that somehow fixed the issue.

Oh and one more thing, my mods list isn't too big but i do have an cold air intake and a mid muffler delete. (just an fyi)

 

first of all was your battery recently disconnected, when you had the idle issues (computer might have to relearn...)


and those two screws, where they the ones holding it to the throttle body? if so, BUY the PROPER TOOL, it was probably a torx if anything

 

iirc 03s have to do an idle relearn procedure- Im sure its been posted many times
do a search for idle relearn,,if its not in the diy already

 

I may get a more than 16 around town, put I gave up keeping track of it because it was depressing. I just take the attitude that I enjoy the car and however much gas it takes is what it takes.

 

when the yellow light comes on,,sometime that day I add about 50 bucks of gas and keep going

 

yes that's true, but for a 3.2 V6 it should be not as bad as a V8.. my old mercedes was a 5.5 V8 and it ate just about as much gas as this car. and thats SAD. went through just about all of the above and it did improve slightly but not as it should. would different tires effect anything? cause i have mixed rubbers. (had some flats, replaced with almost new for 30$ a piece)

 

tires have a major impact on mileage--have you ckecked the pressure and adjusted per our suggestions,,

As soon as you hit VTEC rpm, it turns into a V8 in terms of power and fuel consumption
Try keeping it under 4000 rpm and see what a tank gets you,,,280-350 mixed would be normal on my 01,,,I think the wife doesnt limit the rpm~