: 1200x667 px
: July 2, 2018
An old oxygen sensor (say, 90,000 miles or more) may still work well enough that it doesn’t trigger the check engine light but could still hurt fuel economy. Engine performance can also be reduced by more serious internal problems, such as valves that don’t seat properly or worn piston rings, or by restrictions in the exhaust system. Because the same symptoms can suggest different problems, and there are often several possible causes and cures, it’s better to consult a professional mechanic than to try to be one if you have neither the experience nor the right equipment to diagnose drivability problems. In short, rather than ask for a tune-up, tell a mechanic what you’re experiencing and ask him or her to find the cause.
A dirty or clogged engine air filter is more likely to reduce acceleration than fuel economy, according to tests conducted by the EPA. Because filters get dirty gradually over time, you might not notice a small but steady loss of performance until your car is accelerating like a turtle. But if you haven’t changed the filter in a couple of years (or sooner in areas that have a lot of soot in the air), that could be part of the problem.