So as most of you know, I have an 08 Hyundai Elantra that just hit 60,000 miles. I am up to date with all my maintenance. I use to get 420 miles a tank. Now I am lucky if I get 360!! I mean lucky! I just took a road trip from Vermont to Long Island and my car could not make the trip one way without filling up!! I got gas at 349 miles and put 13.1 gallons in it. That comes out to 26.6 miles to the gallon!!! Which is crap for highway on an Elantra. I have been experiencing a decline in gas mileage over the past few months. I thought the decrease in mileage was because I was driving short distances around Burlington, VT so I waited for this trip to be judge. So I called the dealership, here in Vermont, like an hour ago to discuss this with them. Now a month ago I had my 60,000 mile service done there and I had them clean out all the carbon build up. Ready for this I quote: "The average Elantra gets 340 miles a tank." That is what the person at service told me. I had my calculator on hand and I computed mpg for 340 miles. That comes out 24 mpg! Which is bull crap!! Hyundai advertising the 08 Elantra 27 city and 33 highway!! I followed up by stating that: "When I took my car to North Carolina just a few months ago I got 430 miles." She wanted to know who my sales rep was and I said I did not buy it from your dealership. She then proceeded to transfer me to sales. I got some managers voice mail. I have no idea why she was transferring me to sales when this was clearly a service issue. So I called back. The lady then proceeded to tell me that I should keep a log of my gas mileage so they can pinpoint the problem. I wanted to say WTF??. I just told you what has been happening with my vehicle. Why do you need it written down with dates? At this point I did not want to start yelling so I said bye and hung up.



So basically my rant is, I am getting shitty gas mileage and the dealership does not give two shits. They are trying to tell me that the average Elantra gets 24 mpg, which we all know this is clearly not what Hyundai advertises.



Any ideas no how to further approach this? Thanks

 

Dirty air filter?



When was the last time you changed your plugs and wires?



What about the fuel filter?



Is your tire pressure low?



Added any major weight to the car, like big sub boxes recently?



Incomplete combustion due to ignition problems, poor compression, worn or broken EGR valve, sticking injectors, old O2 sensor, dirty air filter, and just about anything else that affects how well the engine would run is something to look into if mileage has gotten bad.

 

I will pull the air filter when I get home. I re-oiled my K&N about 10,000 miles ago. I changed my plugs and wires at 30,000. I already brought the new plugs. I'm trying to find the NGK wires I got before for my car. It took forever to find them before. I am so angry because in the process of moving I threw out the wire box with the part number one it.



I will be putting subs in hopefully by March of next year. Tire pressure is fine. I actually keep them at 36 psi.



I can take it to like advanced auto parts and they can check my car for codes right? I had a brake switch malfunction that threw a code but did not make anything illuminate on my dash.



It just upsets me that the dealership is trying to say that that is normal gas mileage for an Elantra.

 

your local gas station probably started switching to the winter blend



prepare yourself for bad gas mileage for the next 5 months or so

 

^^^ This.



Most areas run more Ethanol in their gas during winter. It's going to be even worse all year round if the EPA bends to Cali's demands and approves E20 for national use. Right now, most areas run E10 and only during the winter.

 

it has been a decreasing over the past few months. I have gotten gas in PA, NY and Vermont. So I did not even consider gas. Gas mileage last winter was not this bad.

 

If your brakes are dragging that's a big hit. Changing plugs/wires might also help. In related news, I changed the air filter, engine and transmission oil and filters in my wife's minivan and realized a 7% fuel economy improvement.

 

Replace air filter. Align your front wheels. Add new fuel filter.



Always use NGK Iridium. Don't get NGK wires, get PRD from prdonline.com.



We've only bought 2 Hyundais from the dealer before realizing to stay away from them at all costs. My Tiburon 130k and Elantra 170k have been JUST fine without dealers for 10 years and I think they will be fine without them for the next 10 years. Stay away from those jerks.

 

....ive ran NGK wires for YEARS



40 bux what more can you ask for? i know they arent as pretty as the prd but lets face it shes talkin about gas mileage not pretty



i still say its the fuel

 

Brakes never thought of that!! I just had them done 2 months ago. Holy Crap!!



I will re-oil the K & N tomorrow. My wheels were just aligned a month ago. Already brought the NGK Iridium plugs. i have been waiting for new wires so i could install them together. I just checked out prdonline.com and i dont see wires for the newer elantras.



If I cant find PRD's I will get another set of NGK's. That is if I can ever find them again for my elantra.