Lower gas in tank = lower gas FE?

[NoCO2]

Ok...so this is the only thing I can think of to explain my latest entry...

My last entry was 151 miles with just over 3 gallons used...that's almost 50mpg and before this fill up, I usually used the entire tank (roughly 15 gallons) and I only got, at most, 36mpg. But this time, I just used the first 3 gallons in the tank and managed way better gas millage.

Is it possible that if you use up so many gallons out of the entire tank your FE starts to go down? How else would you explain the HUGE jump in FE for this top off? Am I really getting almost 50mpg in a 12 year old 4 door 2.2L engine car or am I just being fooled by some discrepancy somewhere?

[Arminius]

Loss of vacuum in the tank because of volume?

[Lazarus]

Short fills can have big swings in FE. With such a small amount of miles a little difference in fuel can make a huge difference in FE. Could be the pump could be the fill could be great mileage next tank will tell but take the results with caution.

[Dust]

See what the next tank does. You may have gotten really good this time, but may get really bad next time because the tank didn't get filled.

[NeilBlanchard]

Hello,

Fuel gauges are not linear devices. The top half of my gauge always runs about 20-30 more miles than the bottom half.

[NoCO2]

Regardless of how far the needle was down the gauge (yes I'm FULLY aware they're not accurate, 400 miles on first half, just over 100 miles second half usually) I still managed to get 151 miles to just 3.2 gallons which is amazing. I'm going to top off the tank again tomorrow or tuesday on my way to work since there are 300 miles on the tank now and see if I get near the same results on this one since I haven't used but half the tank so far.

[Lazarus]

Patience

[Greenblazer]

Perhaps when you put the 3.2 gallons in there was still room in the tank. If there was still room in the tank this would explain the discrepency. There are many scenarios that might have caused this. A fautly pump, and air pocket in the tank making it shut off the pump.

Just pointing out a couple of possibilities.

Later,

Allan Greenblazer

[NoCO2]

We shall see...

But, it may be a while, I refuse to fill up while gas is at $4 a gallon, which is just hit yesterday here, so I'm getting on my bike from now on and working hard to get that 150cc scooter I found the other day.

[gamer_jim]

I say go ahead and fill up to full, because gas prices are rising every day where I live. Kinda like hyperinflation. Fill up today because tomorrow it will cost you more for the same amount of gas. I'm exaggerating a little, but our gas seems to go up from week to week here.

Also notice my gas gauge is way off. I've run out of gas with 1/8 left on the gauge, so don't trust them.

Is there a way to get a more accurate gauge?