Loss of fuel mileage number has been going down for years

Hi and thanks for using 2CarPros.

The overall distance to empty is determined by the average miles per gallon. For example, if you have a 20 gallon tank and are averaging 20 MPG, a full tank should indicate 400 miles to empty. On the other hand, if you are averaging 10 MPG, a full tank will indicate 200 miles to empty.

With that in mind, have you driving conditions changed which may result in a lower average MPG? If not, the I would suggest ( and I have no idea what maintenance has been done to date) is to check the air filter to make sure it isn't partially plugged, consider a tune up (which requires the removal of the intake, and if the check engine light stays on while the engine runs, scan the computer to see what codes are stored.

Now with all that in mind, if you remove the intake to have the plugs replaced, I strongly recommend replacing the oil pressure switch when it is off. I have seen many failures. Make sure, however, to get one from the dealer that has been updated.

Let me know if this helps or if you have other questions.

Take care,
Joe

Welcome back:

That is a big change. Cars will use more as the wear, but at 75,000 miles, it shouldn't be that extensive.

If you don't mind, let me know what you find out or what they tell you.

Take care,
Joe

Hello,

If I may jump in here. it sounds like the MAP sensor may have changed but not enough to cause a check engine light which is common. I would run the codes by following this guide.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Here is the location of the MAP sensor in case you want to swap it out. Below. Check out the diagrams (below). Please let us know what happens.

Welcome back:
Let us know. We are anxious to know what fixed it.

Take care,
joe