I'm having some trouble with my 2005 Hyundai XG350L's gas mileage, any suggestions?

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.

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)

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

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

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.

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.

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.

I live in Tennessee by the way so, far from being in the north

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.

Okay I'll get that checked out and let you know if it fixes it or not thank you

I have additional problems as well, the light that illuminates the shifting selections in my automatic shifter is burnt out or not working, how do i replace it and where do i get the bulbs from?

Pull up the plastic trim around the shift lever indicator. Shifter handle removal may not be necessary. Locate shift indicator bulb socket. Remove defective bulb and bring it with you to a good auto parts store. Although I am unsure of the specific part number of the bulb, they should be able to supply it for you.

Okay, I'll get that checked out. also, the "push to open" ashtray and cig lighter compartment on my center console wont lock into the closed position when i press it, any ideas about what to do for that?

Try to clean and lightly lubricate the latching mechanism. If the ashtray is able to removed easily, that would be the best method.

I tried to remove the fake wood trim around the shifter but it feels like I'm about to snap it right in half do I just pull on it or is there a specific way to remove and replace it?

Okay now we're getting somewhere, the plastic felt like it was gonna snap but it didn't its just in there pretty good, to remove it I had to unhook the seat heater buttons and cig lighter and put my car in drive to manuver the piece around it but the light was a diode type thing that had to be pulled thru the bottom and then the blub just popped right out so I'll go to AAP tomorrow and get that part thank you for the help by the way I apoligize for being such a bother haha I'm sure I'll have more questions in the future when I think them up again so I'll let you know

I pulled out the ashtray but I didn't really see what part I was supposed to clean, am I just supposed to hit it with some WD40? Also, I blared my horn yesterday and it sounds like it almost has water in it, I checked the fuse and it looks fine, my engine was looking a bit dirty so after asking the professional at Advance Auto Parts if it was okay if I used the water hose on my engine compartment without any pressure he said it was okay I hosed it down a bit with no problem except for the "watery sound" I get when I blare my horn, any suggestions about this?

Washing your engine without sealing electric connections is never a good idea. There are just too many electrical/electronic parts that are prone to water intrusion and eventual corrosion.

If your horn is not sounding normal, there is a small chance that it can be removed and dried out with low-pressure compressed air, but I believe that you will need to replace the horn itself.

Look around the ashtray for the latching mechanism and lightly lubricate it. It may be toward the back of the opening.

I sincerely hope that all of this advice has been helpful, and any donation would be appreciated as I, and my fellow experts, provide our time and professional advice on a volunteer basis.

Okay, well i was actually going to take the horn out and replace it with this as for the ashtray i'll try that when I get home from classes, I also found a gas station close to where I go to school that provides 100% gasoline, I was wondering if it is better than the 90% gasoline/ 10% ethanol mix the other stations have? I'll make sure I donate! You have been an enormous help thus far.

Also, the "AIR BAG" light stays on all the time, I've taken it to AAP to get the code checked or deleted with no luck, how do I get this fixed?

I was going to get this in place of my stock horn

You will need to identify the error code for the supplemental restraint system. Without the error code number, it could be any component, sensor or wiring within the system.

Also, my air conditioner will only run if it is put on full blast, any reason for that?

Check the blower motor resistor if it will only work on "high".

as for my horn, I was planning on buying a train horn, would you have any suggestions on where I could get that installed or a good placement of the horns and aircompressor?

I can only advise on the replacement of factory/OEM parts. I would consult the aftermarket horn dealer for installation instructions.

okay that's what I tought it would be. Also, when I roll my windown down about half way and I let go of the button the windw "skipps" or "hiccups" downward, any reason for that?

Gotcha, I also found a gas station that uses 100% gasoline instead of the usual 90%/10% the other stations use, is the 100% going to give me better preformance for my money or should I stick with the 10% ethonal brands?

Check the power window regulator for the window issue. Ethanol blended gasoline will not affect fuel mileage a substantial amount.

Would you recommend the cheapest ethonal fuel or the slightly most expensive 100% gasoline fuel?

Check your owner's manual for recommended octane; ethanol blends are ok to use.

I also have a few dents in my cars body as well as a prett noticeable gash on the front bumper where I hit a wall, any ideas on how to get those fixed or any products I could use? The gash on the fron also affects the chrome trim on the front left side, how do I get that fixed?

My fog lights were burnt out so I got them replaced, I went to AAP and got the little light bulb for the shifter selector, so those two things are fixed and marked off of my list, I found another problem, I am missing a piece from under my hood, I'll attach a picture of it so you know what I'm talking about

More specifically here.

Still there? Haha, haven't gotten a reply from you in a while

As far as the dents are concerned, I would contact a local reputably body shop for an estimate.

The missing piece is your other horn. It seems that the housing has been broken off.

Well crap. Could that be the reason my horn isn't working correctly? Would I be able to get that piece at any auto store or would I have to get a specific part at a Hyundai dealer?

Could I just take the other horn housing out and put in into a bag of rice or something to soak up the moisture or would that not address/ make worse of the problem? and does the other horn housing just screw back on or is there a different way to get it on, there aren't any instructions in the owners booklet for this problem.

For my bumpers chrome trim I'm just going to find a piece off of an old car at my local Pull-A-Part so do any of the Hyundai models have similar or exact parts as my 2005 Hyundai Xg350 that I can get?

And does the front bumper's chrome trim piece come off or is it attached to the bumper?