'06 Santa Fe - Horrible Gas Mileage and Other Issues
 

We have an '06, 6 cyl, 3.5L Santa Fe that is averaging 200 miles to the tank (mostly city, rarely highway). This has been an ongoing issue for the past 1-1/2 years. We've had it in the shop for 4 months in a row now but they can't figure out what the issue is.

Another problem is that it periodically/sporadically lunges forward when first accelerating after being at a stop. Another issue they can't figure out.

And, on a cold start it sounds like a diesel and makes a loud sputtering sound for approx. 1 minute. Still something that we've never gotten to the bottom of.

Does anyone have any insight/suggestions for any or all of the issues above?

Thanks so much for your help!

2WD or AWD? 200 miles per tank with all city driving isn't that far off. The 2006 Santa Fe has a 19 gal tank and a city rating of 15 mpg. So assuming you fill up when the gas light goes on (usually with about 3 gal in the tank) this means you go 200 miles on 16 gallons. 200 miles / 16 gal = 12.5 MPG. That's a rough estimate but not too far off.

Is the car in tune? Are the tires fully inflated? Do you use a remote starter and or let the engine idle a lot? What are your exact mileage / gallons? Fill up the tank and write down the mileage. Drive your usual 200 miles or so and refill the tank. Tell use the exact miles and the exact number of gallons on teh refil.



Are you using a Hyundai oil filter or an aftermarket filter? What weight oil?

It's an AWD automatic. When it's really cold I will let it idle for 5 minutes in the morning before taking off. It's been warmer lately so haven't done that in the last few weeks. As far as we know, the car is in tune. The shop hasn't said anything about needing a tune-up. What type of mileage should we get on the highway? Maybe we'll take a weekend trip to see how many miles we get to tank on the highway.

We are using a Napa oil filter and 5/20 weight oil. Is this the cause of the sputtering sound?

Thanks for your help :)

I should also mention that we have been using the same oil filters and oil since we purchased the vehicle in 2006 and yet it is only recently (4 months or so) that this problem with the sputtering began.

Also, current mileage is 30,800 if that makes a difference in any of this.

Thanks again.

I'd say that's the reason for the poor fuel economy. That and driving a 4000-lbs vehicle 100% in the city.

The AWD auto 3.5L is rated at 21 mph on the highway.