Dear Doctor: I have two problems with my 1993 Honda Civic. First, with the cold weather the trunk gets really wet. How can I prevent this? Secondly, the car is burning too much gas lately. I was getting 30 miles per gallon, but now I’m getting only 24 mpg. Why? Frank
Dear Frank: Water or wetness in the trunk needs to be checked for its port of entry. Dampness can sometimes be found under the spare tire in the bottom of the fender wells. A water test can also be performed to locate the source of entry by running water over the rear roof section slowly to see where it may entering the trunk. A loss in gas mileage during cold months is due in part to a change in the gas mixture, the engine running colder, plus lights and heat causing the alternator to work harder. On all fuel-injected engines attention should be paid to the air filter, spark plugs and the oxygen sensor. I also recommend a backpressure test for partly blocked exhaust systems and catalytic converters. The engine temperature is an important part of engine operation. It has to be at 185-plus degrees for optimum performance and economy.