Going through my receipts I came across some good news re: my 4104, 11 mpg!

[johns4104s]

Be sure that you change the primery filter located on the bulk head above the transmission.

[gus]

Zub,

That pretty much agrees with what I recorded during a trip through AR, MS and LA a year ago. Not many hills on this route except near my home in North AR. That was the only time I ever checked it out on level ground.

When  I make a trip west through the Rockies and up the west coast it drops down to 8-9 but that is still pretty good.

My 4104 is strictly stock like yours.

[DSweet]

On our "maiden voyage" with our '04 on the flat in the San Joaquin Valley here in California, we managed 9.25 mpg, the Grapevine which is
a tough climb knocked our average down to 7.1 over all for out trip of just under 600 miles.  We are pleased with the mileage, it isn't good
for a car but it isn't bad for a house!  We towed out Chevy Cavalier four wheels down.
Blessings,
David
PD4104-2977
Winton, CA.

[WEC4104]

So it sounds like your speedometer and pretty much all of your other gauges are out of commission. Yet your odometer is still working? Or did you use some other means (GPS, Mapquest) for the mileage calculation?

[gus]

I don't use my odometer anymore, the GPS is far more accurate.