Q–My 1990 Ford Mustang GT has about 120,000 original miles. The car is still running great, but the check engine light intermittently comes on. I have changed the two oxygen sensors and the problem still exists. Could you please tell me what I should do next before I take it to the dealer for diagnosis? T.P., Chicago
A–You made a bad guess that the oxygen sensors were at fault. (Ford calls them EGO sensors and, if that is what they do, we know some annoying people who would set off everybody’s check engine light within 50 feet.) Guessing is no way to find a problem with the engine control system. Have a professional technician diagnose the problem. By the way, it is a good idea to change your oxygen sensors regularly, so you didn’t waste your money.
Q–I am looking for a copy of your column that appeared in the May 25 issue of the Sunday Tribune. Please, please let me know how I can get the column. B.B., Skokie
A–Glad you asked You can get Motormouth columns, current and past, on the Internet at the Chicago Tribune Web site (www.chicago.tribune.com/autos). When the page loads, click on Motormouth.
Q–I have a 1990 Mitsubishi Eclipse GS. About two years ago, I returned from a five-day trip to find my one-year-old car battery dead. I bought a new battery. Since then, I have gone through several batteries. Basically, any time I do not drive my car for more than one day, the battery dies.. When I’m not going to drive it, I hook it up to a battery charger so I know it will start.
The Mitsubishi dealer couldn’t find anything draining the battery, neither could a private auto repair shop. Any ideas? D. C., Chicago
A–All modern cars have parasitic power draws to keep computers alive while the car is parked, but the maximum should be less than 50 milliamps. Ask your technician to check for other key-off power demands. Glove box, trunk and vanity mirror lights are suspects. A glove box light can draw about 150 milliamps–enough to kill a battery in about three days. If the parasitic draw is within reason, the charging system may not be pumping enough energy back into the battery.
Q–I have a 1990 Volkswagen Corrado G-60. When I start the cold engine, the idle speed is usually too high, about 1,250 r.p.m. The engine speed remains at this level, especially in neutral, but after some driving, it usually drops to 750 r.p.m. However, when I engage first, second or reverse, the car seems to accelerate by itself and the number of r.p.m. jumps to 2,000. When I depress the clutch and shift to neutral, the engine speed returns to about 1,250 r.p.m. I have been told that it could be related to fuel injection. M.S., Franklin Park
A–This is dangerous and can cause engine, clutch or transmission damage . If the engine speed was always too high, we would have suspected an air leak in the intake system, allowing the engine to get “false air.” However, it seems that the engine control computer is getting a command to speed up. This kind of problem can be difficult to track down, so be patient with your technician who must be thorough, careful and methodical.
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Bob Weber is an ASE-certified Master Automobile Technician. Send questions to Motormouth, 17717 Silcott Springs Rd., Purcellville, Va. 20132. Send e-mail, with name and hometown, to motormth1@aol.com. Answers are supplied only through the newspaper.
