Q. Last year on a long trip our 1996 Dodge Ram Van ran fine until about 20 miles from our destination when the engine started missing violently. The car slowed down to about 25 mph and whenever I tried to accelerate, the “check engine” light would flash about eight or nine times, start missing again and slow down. I nursed it to our destination and then took it to a local garage. When I returned home I took it to a service center. They found the crank position sensor intermittently out of range and the air intake sensor out of range which they said “would cause lean running.” When I replaced both of these items, the light went out and the engine ran fine until it got to less than a half-full gas tank. At that point it started to misfire again. I took the van back and was told that the fuel rails were rusted on the inside, which is common with the 5.2 engine. I have not yet done this job, electing instead to keep the gas tank filled over half full. We are planning to take a trip south within the next few months and I would like to get the van running properly again. Maybe you could give me some advice about this condition.

— Everett

A. I would ask your repair shop to perform a fuel pressure and volume test. It is possible that the fuel pump has become weak and that will show up when the volume test is performed. As for the fuel rail problem, rusting has been a problem. Combine the restricted fuel rail and a weak fuel pump and it is easy to see how the engine could misfire and buck.

Hyundai problem is draining

Q. I bought a 2000 Hyundai Accent new in 2000. I mostly use it on weekends and have never had any problems until this past year when the car started needing jump starts. Recently, I bought a Sears Die Hard battery, but I continued to have this problem. I had Sears check the battery and it was fine. Then I had the Hyundai dealer check the electrical system and was told it was fine. What could be draining my battery? Is there something that an electrical diagnosis is likely to miss? Is there a tool that a layperson can use to find out if something is activated?

A. Start with a basic check of the charging system. Something as simple as an overlooked alternator drive belt could be the cause. The other possibility is an electrical component that is not shutting down after the car is turned off. Possibilities include the courtesy lights, the sound system and the alarm system. A repair shop needs to check for parasitic drain to determine whether there is a problem. With the exception of looking for trunk lights and other courtesy lights staying on, there isn’t much you can check without specialized tools.

Service bulletins could point to trouble

Q. It seems that when my 2006 Pontiac G6 is low on gas, not low as in about to run out of gas low, but a quarter of a tank or under, the check engine light comes on and my car revs violently when it comes to a stop. Sometimes it revs but the car will stall. This can happen at speeds of up to 35 miles per hour. I don’t want to go into repair shop and be like, “ uhhh my car is broken can you fix it?” I would like to go in there knowing something about the car problem so I don’t get a high price on a repair that may be only a small fix.

A. The best thing to do is bring the car to the dealership when the car is experiencing the problem. The check engine light will help the technician narrow down the problem. There are at least two technical service bulletins that could apply, one is for a damaged computer chip in the power-train control module and the second is for a damaged wiring harness. Both can cause a symptom similar to the one you describe. Ask the repair shop for an estimate before any repairs are performed.

Factory mats perfect fit

Q. I just bought a new car and was shocked by the cost of floor mats. The price on the invoice was $100. It seems to me I could buy mats at a department store for $20. Are the factory mats that much better?

A. The factory floor mats are an exact fit, generally don’t slide around and will stand up better than most of the “aftermarket” mats. In addition, most department store mats won’t be an exact color match. Enjoy your new car and the new mats.