EGR and fuel mileage?

[Cole94]

I have a 94 explorer XLT 4x4. I am getting roughly 13mpg with 90% of my driving being 45-55mph. My DPFE sensor is faulty, getting the code for it and it opens too much with very slight throttle application, even in park, causing very bad stumbling. I currently have the vacuum line pulled off at the tree, and a cap on the vacant hole.
A new sensor is $50 shipped from rockauto, $75 if sourced locally. Is it going to help my fuel mileage to replace it? Or should I leave it disabled? No driving issues at all with it capped off, just poor fuel mileage. Also, my check engine light bulb is blown so I cant see it .
Or is 13mpg the best I can hope for with the age of this truck and sitting at 270k miles?

 

[MrQ]

13 MPG is pretty low. My 4WD '93 on 33's with a stick makes 15 on the highway.

Replace the sensor. The computer is looking for that DPFE sensor input and needs it to run the engine properly. Only way to get around that is to put in a computer from a '93 which doesn't use EGR.

 

[Roadrunner777]

Yeah, sometimes when a computer sense a fault, it falls back into a 'safe' calibration so the fault doesn't cause engine damage. It's a very conservative cal, it retards timing among other things. Get it fixed, and your mileage should improve.