: 1440x834 px
: June 25, 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.
If your vehicle does not use an automatic tensioning device, then check belt tension as follows: With the engine turned off, grasp the belt at a convenient point about 8 to 10 inches from the alternator pulley. Move the belt slowly up and down. The belt should not move more than about 12 inch. If the belt seems to be excessively loose, then of course it will require tightening andor replacement.