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No. 1: Replacing oxygen sensor(s)
Average repair cost: $249.92
For the sixth year in a row, oxygen sensor malfunctions remain the most common car repair, accounting for 7.01% of repairs in 2015.
The so-called O2 sensor can fail as a result of neglecting car reairs, engine issues (such as internal leaks or burning oil) or simply from using gas with a higher concentration of ethanol. Because the sensor works with the car's on-board computer to create the fuel-to-air ratio, a malfunction can result in as much as a 40% drop in fuel economy and can affect performance. The average cost of the repair decreased $10 from the prior year.