I have a 2001 Excursion PSD and would like to get some help.
I have changes all the filters, oil, and kept it well maintained. The last three months my gas mileage has dropped from 17.0 mpg to 16.3 miles per gal with no change in the way I drive the vehicle.
I don't want to put a chip in it because I don't want to void the warranty.
Any suggestions has to why it would go down hill so fast.
I have 48000 miles on the truck and it is completely stock.


Thanks

Slant 7
Wickenburg Arizona
70 miles Northwest of Phoenix Arizona

 

One reason Fuel mileage goes down on a psd is dirty oil, or bad fuel filter. Blocked or dirty air intake will also cause bad fuel mileage..

have you drained the water separator recently - if not you could have gunk in there that is causing you fuel mileage to drop.

(PSD do not have gas mileage... )

Theo

 

I change the oil every 4000 miles and just changed the fuel filter and air filter. Not sure where the fuel separator is though.
Slant7

 

The mileage varies from time to time with driving conditions. Unless it's been like this, I wouldn't worry too much if it dropped 1-2 mpg. Have you run a fuel additive through a full tank yet? You probably have dirty fuel injectiors. I have a 2001 like you do and the mileage was dropping on mine too. I ran some of Power Service's Diesel Kleen and my mileage started to get better. It also gave me a little more power overall, it was just like the day I drove it off the lot. Power Service's Diesel Kleen comes in a silver bottle and treats 2 tankfuls per bottle. I use it whenever I fill up and since then, my mileage has jumped up a few points. Diesel Kleen is the "summer formula" of Power Service's fuel additives. It's about $3-$5 per bottle at wal-mart. If you live up north where it gets cold, use Stanadyne. It's hard to find, but it's worth using if you can. If you can't find it, use Power Service's "Diesel Fuel" (the white bottle) Both these additives have an anti-gelling agent to prevent your diesel from freezing or gelling in your tank and fuel line. Try that and see if it gets you back up to 17mpg.

 

I will try that this week.
THANK YOU!!
I live close to Phoenix Arizona, I do not have to worry about freezing fuel.

Slant7

 

Just out of sheer curiosity, what color is your X? Limited? XLT? 2-wheel drive? 4-wheel drive?

 

2001 XLT 4X4