: 1000x1409 px
: July 2, 2018
In case you don't know who take your car to for auto electrical repairs, you can ask for references from fellow motorists; ideally friends and relatives who are unlikely to mislead you in this (potentially sensitive) matter. As long as they have faced such situations before, they are likely to guide you on which service providers to visit; or at least which service providers to avoid.
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.