: 3872x2592 px
: June 25, 2018
You can also perform the test yourself if you have access to a Battery Load Tester, a device which is made for the purpose. The load tester works by placing a specific amount of electrical load on the battery for a specific amount of time while monitoring the available battery voltage. The battery should be fully charged before the test in order to insure accurate test results.
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.