I recently had a lot of work done to my car. Full alignment, new tires, tranny flush, oil change, denso iridium sparkplugs, K&N Filter and a Optima Red Top battery. My car is running great, actually accelerates better than it ever has. My problem is that my gas mileage has plummetted from 26mpg down to 20mpg at best. That is a huge difference and I am wondering why. Are any of the things I had done to my car killing my MPG? I am getting killed at the pumps now. Is there anything I can do or will the problem fix itself? I figure there has to be plenty of people that have experienced this before.

 

winter time is here

by spring u will get better

20mpg is fair, i am getting 22 for winter, 25 for summer

 

dont worry, ive been getting around 19-21 right now. i used to get a good mid-20's just two months ago, so dont worry about it. i try not to drive too much during the winter, its just wasting alottta cash.

 

Have you checked your (cold)tire pressure?
Are the new tires you put on the same as the previous?

If not, the new ones will have different "Rolling Resistance Charateristic" which will impact the gas mileage. You may get some gas mileage back by increasing the tire pressure.

 

They are the same tires as before and pressure is 35psi as before. Is it just the cold weather, because I don't remember my gas mileage being this bad last winter. I thought my deceased gas mileage would have something to do with what I did to my car recently. Any opinions on that topic.

 

the tl seems to suffer from winter blends of fuel. im always down in the winter. none of the things you did to the car would reduce your fuel mileage. and there is no quick fix to help either. unless you have something wrong (usually accompinied by the check engine light) all you can do is just wait out the winter.

you could try a different gas from a different gas station

 

The only thing that I can think of is that one or some of your new spark plugs may have been impropertly gapped?

 

doubt full. if that was the case he would have a rough idle and not very smooth acceleration. and he states its running great

 

Actually, that would be the case is the gaping was off a lot.
But if they are only off by a small amount and not all 6 plugs are off, the ODB-II computer will actually make Fuel/Air mix adjustment to compensate!
In addition, it may not be the winter fuel since he does not remember this low of gas mileage last winter. And not all states are required to use Winter fuel, it is based on the EPA ratings which varies from state to state.

 

all winter states get winter fuel blends. what type they get is determined by the epa rules and laws in that state.

and if they were only slightly misgaped you wouldnt see a 6 mpg loss

 

FYI, PA and NJ are exempt by the EPA this year for the Winter fuel which we had to use last winter!

 

winter fuel blends arent just a epa issue. they have divverent additives in them for helping in the cold weather from freezing as easy and additives to help keep them dryer.

not just for emmisions and the epa so yes they do have winter blends. they just dont have epa regulated ones

 

so plugs probably arent the issue, just cold weather. Also the colder it gets like 20 degrees and lower car runs a little rougher, but not bad, when warmer it runs awesome. I use full synthetic oil and thought that may be the problem, not sure. What do you guys think?

 

Live here in frozen Ohio, run my 2002 tl-s on mobil 1. For better gas mileage try different types of gas . Found that BP, Shell, and Arco go like water. Try Sunoco, or even the gas at Sam's Club all afermentioned at premium. Found if you have a half tank of premium, and add 89 octane (sunoco) the gas is mileage is a bit better with no loss of performance.

 

exactly, its not the cold but the fuels. try different stations. some have different winter formulas than others. its teh winter formulas that seem to hurt teh tl