Edmunds Answers



  • karjunkie 10/22/09 4:11 pm PST

    Changing the oxygen sensors is not going to improve gas mileage unless they are defective. You need to do a tune-up of the car to improve the gas mileage if you have not done so in the last 30K miles. Change the spark plugs, fuel filter and the air filter. A worn spark plug or clogged air or fuel filter will hurt your MPG. Change the PCV valve and clean your EGR valve as it may also contribute to low MPG. The PCV valve is very important, if it’s clogged your gas mileage will go way down. It just pops out of the valve cover and is an easy fix. The EGR valve is connected to the intake manifold and can be removed and cleaned with throttle body spray cleaner. Make sure your injectors are clean and functioning properly. Run some Techron Concentrate injector cleaner through a couple of tanks of gasoline. Clean the MAF sensor wires in the intake plenum with CRC sensor spray as dirty sensor wires will cause you to run rich and burn more gas. Lastly, start running only tier one gasoline in your vehicle. I only use Chevron or Shell and have very few problems with the throttle body or injectors fouling. Good luck and let me know if you have any follow up questions!


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