Ok This is driving me nuts!!! The last time I tested my gas mileage I looked at where the needle was and then filled the tank up and recorded the gallons. When the needle was in the same spot I recorded the miles. I then divided the miles by the gallons and came up with something around 19 mpg. This is on a 2.3l 4 banger and 5 speed manual. I know this cant be right. So I was wondering how yall test mpg. The needle changes constantly so I know theres loopholes there. But I dont want to run the tank dry and risk getting stuck in the middle of no where with no gas.

How many miles do I get after the fuel light comes on? If I drive till the light comes on everytime this would give me a better perspective of how many miles I have left and when I need to fill up next before I run out of gas.

Any help would be appreciated, I am pulling my hair out over this!!!

 

Try reseting your trip meter every time you get gas. Then simply divide miles by gallons as you were doing. It makes no difference if your at 3/4, 1/2, 1/4 when you fill up. Also pay attention to how you drove(heavy foot/ light foot/ city/ hiway/ or combination) for that tank. After awhile you will get a general feel for the mpg's during any particular tank.

As far as how much gas is left when the light comes on, this will vary by vehicle. However, it's been my experience that the light indicates about 40-50 miles left in the tank. Vehicles with higher mpg ratings will have less gas than the lower mpg rated vehicles. That being said - don't take my word on that and try and drive those 40-50 miles without checking your vehicle. Here the solution would be to try, over a number of tanks, to get gas as soon as the light comes on. Then simply subtract the amount of gas you added from the tank size(20 gallon tank?). This will give you an idea of how much fuel is left when the light comes on.

Then by knowing the general mpg's you can estimate on the fly and determine if you've got enough to make it to the cheaper station up the road or if you should pull over and pay the extra 30-50 cents a gallon at the expensive place.

My old Mazda/Ranger's gas gauge would "float" a bit so the trip meter was a better indicator for me. Although I wouldn't discount the gauge reading altogether. My gauge started floating more and more just before it stopped working completely. I drove around without a gas gauge for 3 years and never once ran out of gas.

 

I do reset my trip meter. But how do I know when I used as much gas as I put in? Maybe im confused by what you said.

 

I fill the tank up(17 gal), reset the trip meter. I drive it until the red light goes on. I then divide the total miles by 17 and walla; 24 mpg. on a 2.3 auto 2006 Ranger XLT.

 

Simply...
1.) Fill up your tank until the pump stops due to the automatic pump shut off
2.) Reset the trip odometer
3.) Drive...
4.) When approaching empty, fill up once more until the pump stops due the auto shut off and record the amount of fuel it required to do so.
5.)Divide the number of miles on your trip odometer by the amount of fuel that just went into your truck.

I beleive this process is the most accurate way of determining the amount of fuel used in a trip. Reading off of the gauge directly is VERY inaccurate.

 

Also, if you can use the same station and pump and do it over several tankfulls, you will get a more accurate MPG.

 

I just divide the miles driven on my trip meter by the gallons I put in. Don't forget to reset the trip meter every time!

 

CrazySpyder69,

You won't know exactly how much gas you used until you refill. However if you track your mpg over a period of time you will get a feel for the average mpg's your truck gets.

Then, you can divide miles driven by your average mpg's and you'll have a good idea how much fuel you've used.

Example:
Say your truck gets 20 mpg city and 25 mpg freeway

Fill the tank
Reset trip meter
Drive 100 miles

In city driving you would've used 5 gallons (100 miles divided by 20 mpg = 5 gallons)

On the freeway you would've used 4 gallons (100 miles divided by 25 mpg = 4 gallons)

Hope this helps.
Tim

 

This is a really accurate way. Thx for the help, I will try this one on my next fullup!

 

I too, use the trip odometer to calculate my mpg at every fill up, BUT I don't make it a habit of running my tank low enough to have the check gauge lght come on!!!!

As the fuel pump depends on the fuel to cool it, low fuel levels will cause it to run hotter than designed & shorten it's life.

I refill at the 1/4 remaining point. In summer this is even more important.

Just a side thought for consideration!!!!

 

+1, and you don't have to empty the tank. You can fill up anytime and still calculate the mileage. Miles driven divided by gallons used. Anything else is quesswork. jim d