i have a 04 TL at, the thing is the best mpg i have ever got was 22, now i put 18's on which i dont think should make a huge difference now im at 18mpg consistently. the car has 87k on it, change oil every 3500 i have not done the plugs yet. i ahve only had the car for 7k or so of its life.

any suggestions?

i have k&n filter, cut my mid muffler and resonator out but thats it when it comes to mods on engine/exhaust.

 

Idk what to tell ya' man. My mpg's worse. Right now I'm averaging 13-15mpg (100% city driving) and IDK what the hell to do. It's running me dry now. I don't want to open a whole new thread for this so I'll ask here, do you guys reset your MPG/Avg Speed every time you guys fill up? I do, but Idk if I'm supposed to or not.

BTW, I think your car and my car are identical judging by your avatar. lol

 

how r your driving styles? lead-foot? or grandma-like? i Reset MPG after a fill up and i average about somewhere from 18-21 city driving and 26-28 hw driving. But i recently made a 250miles trip from NC to DC and i average 32 MPG with 4 adults in the car and a trunk full of stuff. I use Shell 93 only and drive like a grandma.

 

grandma style most of the time, chevron 92 is all i run... washington is kinda wierd cause its a 50/50 split all the time for city/hwy which sucks but oh well

 

Make sure your tire pressure is not low. How about the air filter, when was the last time you changed it?

 

Seafoam FTW. I got an extra 3MPG after I did mine

 

That's not out of the ordinary. Search for my mpg vs mph thread. MPG seems to follow your average MPH closely. In pure around town driving with an average mph or 17 or so, I get 13-14mpg driving very easy. Pure freeway driving with an average of 65mph I get 34mpg.

These cars aren't light and the weight really hits you in acceleration. In steady state without hills the weight doesn't hurt nearly as bad as getting it up to speed.

What's your average mph? Are you using premium?

 

sticky tires lower mileage but increase fun factor~
Plugs with 70 on them are ready for a change- NGK Iridium ONLY
Seafoam it first and get the TB plate clean too- makes a difference
May be ready for EGR port cleaning (if same prob as gen2 has)

 

right on thanks guys! i work at schucks so i can get that stuff dirt cheap i will give it a shot.

 

i heard seafoam was bad o_O

 

I personally don't like it but so many people use it I don't bother saying anything. You can get the same results with water sprayed into the inlet tract.

In the oil, you never ever ever use a solvent in there. It dramatically lowers the film strength and HTHS rating of the oil. If you do use it in there, it should only be used at idle, not driving and even then I would be nervous.

In the gas tank, it's debatable, I've never looked into it enough to know if it does anything so I won't say it won't help. However if you use premium top tier gas for the car's entire life, injector and fuel system cleaning should never have to be done. The rather large maintenance dose of cleaners in the good fuel is more than enough. It would be like using Seafoam on a brand new car and saying it made a difference. If there is no problem to begin with, you can't fix or improve anything.

 

dont accel so low. ur making ur car work harder at low RPMs since the TL is so heavy. i gained like 2 mpg just by picking up the pace when i drive.

 

Especially true in the 5at where the torque convertor is less efficient the lower the rpms and the less throttle you give it. Obviously there's a fine balance, you don't want to floor it either.

 

maybe resetting ECU might help ? Feel your pain about the MPG as those # are indeed low IMO ...

 

My other TL, and '05 and the wife's, is an automatic and her average for "town" driving is 25 MPG. But "town" for her is largely open roads unless she heads into Manassas, Fairfax, or Falls Church as she does sometimes. She uses no special driving techniques and is a little more aggressive on the throttle than am I with my '04 manual. When we are on vacation with her car and are therefore at a resort for a week, her MPG still doesn't drop below 24 MPG. And during the warmer months, she always uses her A/C.

My '04 manual TL sees more in-town driving, such as Manassas and Fairfax, and its average mileage in the winter is 24 MPG.

Keep in mind folks that your engine will deliver lower fuel economy in the winter, or cooler, months than in the summer, or warmer, months. This is due to several things outside of the differing driving habits during the cold. During the colder months, there are additives which are placed in gasoline (oxygenate) to help reduce emissions. Also, colder air is more dense - more oxygen molecules per cubic foot, than warm air. The engine's ECU receives information about the combustion going on in the cylinders and will richen the mixture (increase the fuel shot) and bump the timing a little to compensate for the added oxygen. This is why your engine feels more torquey when its cooler outside. In the summer, fuels are not oxygenated and the air is less dense. So the ECU does the opposite from what it does in the winter. So in summer you will get better fuel economy but produce less power; in the winter, the reverse is true.

 

I average 17-18 in town.... A recent interstate roadtrip netted a 31mpg average @ 80ish with a trunk full of junk.