Mechanics

I'M HAVING SOME TROUBLE WITH MY XG350L'S GAS MILEAGE, ANY SUGGESTIONS?

2005 Hyundai XG350 • 90,300 miles

MPG is less than it used to be.
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Lucky777c4
October 4, 2011.



Has the vehicle been maintained properly? When was the last major tune-up? Are tires in good condition and properly inflated? If there are no driveability issues or diagnostic trouble codes, fuel mileage drop-off can usually be attributed to a lack of proper maintenence.

Dan_K
Oct 4, 2011.
I've taken the best care of this car. I can honestly say it is the best looking 7 year old car I've ever seen. I've had it tuned up recently, tires are always in good condition and inflated, although they are going to need to be changed soon. No codes have come up recently, however a code for a leak in the evaporation emissions value has come up in the past accompanied with the check engine light, but it soon went away. I've even taken out the spare tire to lessen weight, the car is constantly clean and waxed, I used to fill it up in the beginning of the week (when gas was more expensive) and now I have to fill it up about half way thorough the week (even with gas being cheaper)

Tiny
Lucky777c4
Oct 4, 2011.
Has the evaporative emission issue been addressed? Just because the light went off, does not necessarily mean that the fault is no longer present.

Dan_K
Oct 4, 2011.
It hasn't, but the mechanic said that it wouldn't effect anything, I couldn't say if he was right or not.

Tiny
Lucky777c4
Oct 4, 2011.
Some forums say that filling up with premium or plus helps a lot with your engine and I've yet to try this because of the extra cost.

Tiny
Lucky777c4
Oct 4, 2011.
Has the mileage dropped of significantly or just a small percentage? If you live in a northern area, the use of oxygenated fuels may already have been implemented. During the Winter months many fuel distributors provide gas stations with a different (oxygenated) blend of fuels. This would explain a slight decrease in fuel mileage, but not a large one.

I don't agree with the use of premium fuels unless the manufacturer specifies it. Use only what is recommended in your owners manual. Higher Octane fuels are usually only required for abnormally aspirated vehicles. Cars with turbo- or superchargers.

Dan_K
Oct 4, 2011.
It's been a pretty good amount, like I said I used to fill up once a week now its up to two times a week even with the decrease in the fuel prices like I said I've taken most measures to increase my milage with no luck, I've decreased the weight of my car inflated tires used a fuel cleaning fourmula I drive carefully, no luck still.

Tiny
Lucky777c4
Oct 4, 2011.
I live in Tennessee by the way so, far from being in the north

Tiny
Lucky777c4
Oct 4, 2011.
If it is significant, but no "driveability" issues are present, I would still consider pursuing the original Check Engine light. Have the evaporative emissions system checked out by a trusted repair shop. The evaporative emissions system consists of a fuel vapor cannister, a solenoid vent valve and associated hoses. The system is designed to collect fuel vapors in your fuel tank and direct them to your engine to be burned. Before tougher emissions laws were enacted, these fuel vapors used to be vented into the atmosphere. A large evaporative emissions leak could indeed be your problem.

Dan_K
Oct 4, 2011.
Okay I'll get that checked out and let you know if it fixes it or not thank you
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Tiny
Lucky777c4
Oct 4, 2011.
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