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Q: Miles to a fuel of tank changes

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My car usually says I get 380/400 miles when I put a full tank of petrol in. Lately it's saying much less, 350. Obviously the tank size is the same so same amount of fuel going in so why does it change?

My car has 87000 miles.
My car has a manual transmission.

Hi There, Your car has It has a fuel flow meter allowing it to compute miles per gallon on a constant basis. It also has a less-accurate level sensor in the tank, allowing it to approximate the number of miles left given the current trend of fuel mileage. Some fluctuation here is normally ok, however if it continues to decrease, you may have other problems causing this. Your fuel mileage may change for many different reasons such as temperature outside, driving habits, a bad camshaft position sensor, a clogged EGR valve or catalytic converter and many other reasons. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle if the mileage gets worse.

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