Why is my gas mileage so low?

Q. I have a 2013 Hyundai Sonata with a four-cylinder engine and have been getting only 14 miles per gallon. According to the sticker I should be getting 24 miles per gallon. Do you believe there is something wrong with the car?

A. The last Hyundai that I drove returned mileage in the mid twenties. Of course, if you drive very short distances the mileage will be significantly lower. At this point I would perform a simple mileage test. Fill the fuel tank slowly and stop as soon as the gas pump clicks off the first time. Drive the car 100 miles or so in a good mix of city and highway driving. Then refill the tank using the same technique. Divide the miles driven by the gallons used to get your vehicle fuel use. If the mileage is still low I would return to the dealer to have the car evaluated. Also keep in mind that the fuel mileage will improve as you put more miles on. I have seen some cars take 10,000 miles before the engine is completely broken in and optimum mileage is achieved.

Q. I have a 2005 Lexus E330 which has approx. 95,000 miles. I am wondering whether or not I should change the timing belt and the water pump. My second question is does this car have an interference or a non-interference type of engine that I need to worry about?

Advertisement - Continue Reading Below

A. The engine in your car is considered a “free-wheeling” engine, which means that if the timing belt breaks, the engine won’t be damaged but the car will stop running. Your car meets both the time and mileage to consider replacing the timing belt. If during replacement the water pump shows any signs of wear, replace that as well.

Q. I believe a car should last for a million miles. That said, here’s the situation with my 1997 Toyota 4Runner SR5 4WD. The body is pristine. I work from home, so there is no daily commute. The car is in the garage year-round. I drive about 10,000 miles annually. I brought the car into the local Toyota dealer recently to fix a very slow-drip leak from the rear differential. Both the dealer and an independent shop have told me, separately, that the entire rear end is completely “rotted out” and could fall apart at any time. The shop says it can bring up an entire rear-end from road-salt-free Florida and install for about $5,000. Should I go for the rear-end repair or get rid of the car?

A. The rusting of the differential on these models is very common and the only repair is complete replacement. Before I commit to a $5000 repair with a good used part or aftermarket from a company like trail-gear.com, I would make sure the rest of the truck is not suffering from terminal rust. I would also do a complete mechanical inspection. If the vehicle checks out well, then $5000 to keep a vehicle you like on the road is a good investment.

Q. My 2001 Buick “check engine light” came on a couple of months ago. It came on and went off a half a dozen times. A diagnostic test couldn’t determine the problem and now I need an inspection sticker. I have been told that in Massachusetts the car will get a rejection sticker if the light is on. Where do I stand?

A.The first thing you should do is find out what is actually wrong with the car. If the check engine light is on, there will be a diagnostic code. This code will help the technician diagnose and suggest a repair strategy. In Massachusetts, if the car fails for emissions reasons you will have 60 days to get the car repaired. You can also apply for a waiver or a hardship exemption depending on what is wrong with the car. For more information go to www.vehicletest.state.ma.us.