Originally Posted by not4s4l3

Maybe because it is not your daily driver?

Originally Posted by JFUSION

I didn't think you guys get winter gas down south, if you do it definitely kills fuel economy like a switch occurring as soon as they change over their mixtures.

Avoid gas stations with ethanol mixed into their fuels. You can't avoid it with regular and mid-grade fuels as all companies mix ethanol in there to meet standards, but premium fuel can be purchased from Shell with no ethanol. There may be other companies that do the same but some of them still put ethanol in their premium fuel. Ethanol will lower your fuel economy.

Fuel and spark are to large factors on fuel economy, if you have good fuel and spark you should have good fuel economy. Keep your tires pumped up, use synthetic oils in the engine and diff and you should be golden.

Originally Posted by JFUSION

Those mods won't make your car run richer, if anything more lean. I agree with getting a tune but not for fuel economy reasons.

Winter gas and cooler temps will kill fuel economy at least 25 percent this time of the year, it happens to us up here every year. As soon as we switch to winter gas I see my fuel economy tank, like a switch turned on.

Check your spark plugs.

Lastly, if you have lost some torque with your mods you may notice a loss in fuel economy at part throttle driving, as you will need to be using more throttle to maintain the same speed. Any loss in part-throttle mid-range torque could do that to the car, you can make more power at WOT and high rpms but lose torque at part-throttle steady state cruising conditions. You might be able to guess if your car has lost any torque judging by how it drives.