bizzar increase in fuel mileage

[rg2098]

When I bought my car a year ago I got low 20s in the city and 24-25 on the highway. This is what http://www.fueleconomy.gov lists for my car. Lately I've had a 60 mile one way trip to work usually running at 75-80 mph. Now I'm finding I'm getting up to 29.7 mpg mostly highway. I did a diesel purge a few months ago and it did nothing to my mileage Italian tune-ups are done frequently. Why would it all of a sudden go up? The only thing thats changed was a dose a biobor just for the hell of it.

[Brian Carlton]

flawed data???

[rg2098]

Don't think so. My speedometer is almost right on and nothing else has changed. 363 miles filled up with 12.3 gallons = 29.51mpg. My fuel gauge does not read correctly however. The car has a 21 gallon tank according to the shop manuel and when I filled up with 12.3 gallons it read about 1/8 of a tank but the light wasn't on.

[aklim]

If I fill up till I can see the fuel and it is almost on edge, it takes 3+ gals from the time the pump shuts off. That could skew the readings a little depending on the pressure of the pump which influences the amount of foam.

[rg2098]

When my usual pump clicks, I can see the fuel a few inches down into the neck, only a small amount of foam around the sides but I can clearly see liquid diesel.

[t walgamuth]

both fill ups at the same pump? take the next three fill ups and average.

tom w

[tangofox007]

Originally Posted by rg2098

The car has a 21 gallon tank according to the shop manuel and when I filled up with 12.3 gallons it read about 1/8 of a tank but the light wasn't on.

I would continue to fill up at that pump!!!

[mbzkid]

Odometer stopped skipping?

Finally got that last piece of carbon out?

Same size tires?

I would average it out over 5 or more tanks...

[pberku]

A/C compressor still works?