Hi,

This is a desperate plea for help from one of my customers. He has a 00 Expedition w/ the 5.4L motor; he is generally happy with the vehicle and uses it primarily as his business vehicle but hes noticing a drop in mileage. That is how I came to be involved as he suspected a mechanical problem so he brought it to my shop for repairs.
Before I ever saw the truck he had done some repairs (DIY); specifically, he changed theO2 sensors and did a filter service. I checked that work and also did a full OBD2 scan, then I poked around for anty recent changes; i.e., tires, (size and inflation), highway versus city miles, different drivers, apparent differences in performance, etc. All of this led to zip and I am getting a bit frustrated.
He claims the vehicle used to get 13 MPG and has now dropped to almost 10 although he is at a loss as to why. My questions are ... are these mileage numbers unusual for this vehicle and, if so, any clues as to what is going on; and, are there any good mileage tips or upgrades that I can give him?
Thank you in advance for any help, advice or suggestions you may have.
Cricket

 

IS HE AWARE THAT HIS VEHICLE IS8 YEARS OLD. I AM UNDER THEIMPRESSIONTHAT AS THE ENGINE GETS OLDER IT IS GOING TO CONSUME MORE GASOLINE. YOU SAID HE USED IT AS HIS BUSINESS VEHICLE. HOW MANY MILES?ALSO HAS HE HAD THE INJECTORS CHECKED/CLEANED?HOW ABOUT SPARK PLUGS?

 

Yes, and yes, I checked all of the usual suspects and did a minor tune myself. (the COP ignition is a PAIN is it not?) The change was unusual in that it exhibited stable mileage numbers, then gradually dropped, then restabilized at the lower numbers. I looked for any parameters that would explain the drop, of course.
Anyway, thanks for trying?