I've got a '05 XC90 V8 with 23000 miles. The text message box displays, among other things, ave mi per gallon. In the last couple of months the displayed ave mi per gallon has gone from 18.8 to17.2, same driving. Is this a red flag ? Should I have serviced before the warranty runs out ? Any input and/or advise is appreciated.

Thanks

J

 

I too have a XC90 V8 and prior to it owned a Explorer V8 (200K miles). I am also sensitive to MPG so am understanding of your plight. There are several things to check, but my experience with the Explorer leads to one area you might check first.
- Have you begun using Ethanol? Ethanol has less energy than gas and MPG will go down a little when using it.
- Next, from personal experience, is the fuel injection. You might try some fuel injection cleaner for a couple of tanks. That failing, the dealer can force feed some super cleaner and that will insure your injectors are clean and doing exactly what they are suppose to do, cleanly.
- In no order you might also check:
Tire pressure
Air cleaner
Fuel filter
- Finally.
transmission service
Check w/your service mgr and ask if there has been an update to the ECU. Ford did this with the Explorer a couple of times during my ownership and although there was no recall, they reflashed the ECU when I had the transmission fluid changed and it increased my MPG a couple of miles. Ran better also.
MAS. The Mas Air Sensor can get gummed up with carbon and require cleaning. I haven't removed and cleaned the one on the XC (only 10K miles) but cleaned the one on the Explorer a couple of times with some Chem-12 carb cleaner and light air pressure.

With the exception of Ethanol and tire pressure, the other things I've noted will may only have a small affect, but when coupled together, several small things can make a notable change.

 

Thanks very much for your input and suggestions. We have not used any ethanol so that is not a factor.

I will contact the service dept re: updates and follow your suggestions. I spoke to a service manager last week and he basically said the text info re: mi per gallon is not very accurate to start with and serves as a very rough guide. I'm not so sure I trust this take.

Anyway, thanks, I'll post later to let you know if your suggestions have any impact.

 

Are you sure about the ethanol? Almost all gasolines today have blended ethanol. It is also required by law now to put a sticker on the gas pump that advises "This gasoline contains 10% or less ethanol." Some stations are just now adding the stickers here at my location but have been pumping blended ethanol for some time.
As this reply is some time following your post, have you had your vehicle checked and did you find any problem? Was there any trouble code in your computer?