Many things can cause excessive fuel consumption. First, make sure that none of the brakes or transmission is dragging, or that the transmission is shifting properly. We had a car in the shop recently that had poor fuel mileage and one of the front calipers was dragging against the rotor. (also check the parking brake). Next, is everything up to tune? Good spark plugs, clean airfilter, good PVC, good Oxygen sensors, check for codes, etc. Check if there is a vacuum leak - (use a vacuum gauge). Lastly, if you have access to one, use a emission tester in the exhaust to see what the levels of hydrocarbons are. This will at least tell you if the engine is running clean. Sometimes poor fuel mileage might be a combination of things which all add up, like under-inflated tires, spark plugs fouled, parking brake slightly dragging and poor driving habits. I can always tell the customers who get poor fuel mileage by how often they need new brakes. Someone who lets the car coast and isn't on the brakes much usually gets much better mileage. Those who speed right up to a red light and then jam on the brakes at the last second usually have at least 20% worse mileage. If you need further help, reach me via phone at
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