Tom

Tom,

Q I am having problems with my 1999 Mitsubishi Galant. The car idles

poorly and the service engine light is on. My service technician said it was a
problem with the throttle sensor. So I changed the throttle sensor and put a
new distributor cap and wires on the car. It still runs poorly. What could be
wrong?

Adriana—Goldonna,   Louisiana

Adriana,

A Changing parts without proper diagnosis is a hit-and-miss scenario. It

costs you money and rarely solves your problem. Your car has a minimum
airflow and a throttle position specification that has to be set according to the
manufacturer’s specifications. If either of these parameters is out of
adjustment, the computer will have a difficult time controlling engine idle.
Before replacing any more parts, have your technician perform a throttle
plate cleaning, and set the minimum airflow rate and the T.P.S. (throttle
position sensor) to the proper specs. This should correct your problem. If not,
further diagnostics are required. Good luck!