High-Mileage Car Got A Tune-Up, But Has Stalling Issues

February 13, 2010/Steve Tackett

MOTOR MATTERS ASK THE AUTO DOCTOR BY JUNIOR DAMATO

Dear Doctor: I own a 2003 Ford Taurus with a V-6 engine and 110,000 miles. Randomly, regardless of weather conditions, when the engine is at an idle it will stall. This occurs often when I get off the highway and am sitting in traffic. Some days it will happen three or four times. Other times it does not stall at all. There are no computer fault codes stored. I have had all the tune-up parts replaced. Do you have any ideas? Mary
Dear Mary: A few things need to be considered, including a possible lazy EGR valve and lazy idle air control motor. Carbon buildup in the throttle body will also affect idle speed and quality. In some cases air from a vacuum leak and/or PCV valve can also effect the idle, however this fault would set the “check engine” light and a lean condition would also be in the computer memory. Have your technician disconnect the vacuum line to the EGR valve for testing purposes first. If this does not make any difference, have the tech manually turn the idle screw up 200 rpm and road-test the car again.
Dear Doctor: I own a 2007 Toyota Camry Solara with the automatic transmission. It seems that the transmission isn’t shifting correctly. And sometimes I notice a bad smell coming from the car. When I come to a full stop or yield I notice the transmission downshifts or hesitates and then it will make a hard shift into gear and sometimes I will get that rotten egg smell. While driving on main roads it’s fine. , But if I am getting onto the expressway or in stop-and-go traffic I will hit the gas pedal and the car will down shift for a short period of time, then it will hard kick into gear, sometimes I will get that rotten egg smell. What should I do? Janet
Dear Janet: The transmission is electronically controlled and has multiple sensors, including vehicle speed, load, throttle angle (how far the gas pedal is depressed) and temperature to determine when to downshift or upshift. All of these factors get processed in the computer and then the computer sends the correct message to the transmission on when and how to shift. All auto manufacturers have updated programs that the dealer can install simply by uploading a revised program into the vehicle computer. The rotten egg smell emitting from the exhaust is the result of the catalytic converter doing its job. Try changing the gasoline brand, as well as the octane, by going up or down an octane rating. An occasional rotten egg smell out the exhaust is not unusual and does not mean there is a problem.
Dear Doctor: With our gasoline having alcohol already added do I need to use gas-line antifreeze during the cold winter months? Andrew
Dear Andrew: I would not recommend the use of any form of gas-line antifreeze, unless you know that you’ve gotten water in the gas tank.

2003 Ford Taurus

Dear Doctor: I own a 2004 Saturn Ion. When the temperature drops below 32 degrees the engine does not start. The dealer said the problem was the key and replaced it, but I still have the same problem. Have you heard of this problem? Ken
Dear Ken: I happened to be alerted by a reader of a major ignition switch failure. Have the technician check Alldata and/or Identifix for a history of this problem. You can also check your local AAA office for a list of AAA-approved auto shops in your local area.
Dear Doctor: I’m hoping to get a little advice from you on a high-performance car. I have found a one-owner 2003 Dodge Viper with only 3,400 miles for $40,000. I currently have a 2008 Corvette that I am thinking about selling if I buy the Viper. The Vette seems to significantly outride the Viper. I would appreciate any guidance you can give me. Michael
Dear Michael: You will find a big difference between the two. The Viper is a very different car than the Corvette. The Viper seems much heavier with less throttle response than the Corvette. And before I get any mail from Viper owners, I do own a 1997 twin-turbo GTS. The Corvette is a much smoother and refined car. After driving and owning both vehicles, I find the Corvette is a much better all-around for the average driver. If you are looking for a change, test-drive a Z06 Corvette Z06. At 505 horsepower it is silky smooth. — Junior Damato, Motor Matters

Junior Damato is an ASE-certified Master Technician.

E-mail questions to info@motormatters.biz

Mail questions to: Auto Doctor, 3 Court Circle, Lakeville, MA 02347

Listen to Junior online at www.1460wxbr.com Saturdays from 7 a.m. to 10 a.m. eastern time.

Copyright, Motor Matters, 2010