Q. I got a little distracted last week and let my car run overnight. Eventually, it ran out of gas. I added some gas and it started right up, but did I do any damage to the engine?

A. More than likely you didn’t cause any harm. The two biggest problems are oil contamination from excessive idling and if the engine overheated. Today’s engines have such slight tolerances that oil contamination isn’t as much of a problem as it was in the past. If well maintained, most cars shouldn’t overheat. At this point, I would check all the fluids and change the oil and filter.

Q. My Volkswagen Jetta recently died.  I do some of my own repair work and did a tune up. I replaced the plugs, wires, distributor cap and rotor. The car stated right up and drove fine. I let it sit for a while, and it didn’t start again. I removed the spark plugs, cleaned them, and the car started back up. Could there be something wrong with the fuel injection system?

A. It is possible the fuel injection system is allowing too much fuel into the cylinders causing the spark plugs to “foul.” However, I’m a big believer in checking the basics before looking at more complex issues. The ignition coil that supplies spark to the plugs could be weak. You can purchase an inexpensive spark tester from most auto parts stores for less than $10.

Q. I have a 2008 Hyundai Sante-Fe and want to add a trailer hitch. I don’t plan on towing a trailer, but plan to use the trailer hitch for a bike rack. I have seen trailer hitches priced from $150 to more the $250 with labor to match. Is this something I can do myself?

A. There are several companies that make custom trailer hitches (Reese, Valley and Draw-Tite among a few). These hitches are all pre-assembled and in your Santa-Fe would just bolt to the frame. With the help of a friend, the installation shouldn’t take more than 30 minutes. If you ever decide to tow a trailer, Hyundai pre-wires the car with a plug near the rear bumper. You simply buy the wiring harness from the dealer, plug it in and you are ready to go.

Q. I have a Chevy Cobalt and the door locks don’t always work. I had someone look at the car, and they suggested it may be the switch. I had the switch replaced, but continue to have the same problem. The mechanic put the old switch back in and said there is a wiring problem. He couldn’t give me an estimate to fix it. Do you have any ideas on what could be wrong?

A. It is possible that the car has a broken wire at the door hinge. From the door opening and closing over time, the wires that supply power to the door locks and windows can break. A careful examination of the wires going to the door could reveal the problem. As a check for the problem, the next time the locks don’t work, hold the lock button and slowly open and close the door. If the lock reacts, you have diagnosed the problem.

Q. I recently purchased a car with a built in navigation system. I love the system but when I wear sunglasses I can’t read the display. The dealer told me it is not a problem with my car. What should I do?

A. The problem is that many sunglasses use polarized lenses. It is just the reason that these lenses that block glare that make it hard for you to see your vehicle’s navigation display as well as other LCD displays. This is not a fault of the vehicle, many cars use LCD displays and when viewed from a certain angle with polarized sunglasses will render the display just about useless. On a safety note, you should be listening to, not looking at, your navigation system.