Fuel gauge/Sending unit?

I have an 02 Tahoe and as long as I have owned it, the fuel guage will only go to 9/10 full when I fill it up. At empty (low fuel light) and guage nearly pegged to left, I can only put in 18 gallons of gas. It is supposed to have 26 gallon tank capacity. Do I have a faulty sending unit? I am afraid to continue driving on empty, but could til I run out (carry gas can with me) to see if I still have8 gallons of gas in my tank unaccounted for. Anyone else ever see this problem? Short of dropping my tank this summer, looking for ideas. TIA GRP

mine is very similar to yours. by the time my low fuel light comes on, i cant put more than 20 gallons, so i have a mysterious 6 gallon black hole. i never really pushed it too far beyond the light coming on since i dont carry spare gas. i think its pretty common for the guages to be way off. i had another chevy before my tahoe and that guage was way off too. i could to 200 miles on the first half of the tank, but only 50 miles on the second half of the tank, atleast according to the guage.

I have an 02 Tahoe and as long as I have owned it, the fuel guage will only go to 9/10 full when I fill it up. At empty (low fuel light) and guage nearly pegged to left, I can only put in 18 gallons of gas. It is supposed to have 26 gallon tank capacity. Do I have a faulty sending unit? I am afraid to continue driving on empty, but could til I run out (carry gas can with me) to see if I still have8 gallons of gas in my tank unaccounted for. Anyone else ever see this problem? Short of dropping my tank this summer, looking for ideas. TIA GRP

You could ground sending unit and see if gauge goes to full.
If so the problem would be fuel sending unit in tank.

If you are sure it is a 26 gallon tank I would just refill it when it hits around 18 gallons low.
Do not run a fuel tank over a 1/4 low

How many miles on it.
If a lot of miles some day you will need to replace the fuel pump module that will fix gauge and pump at same time.

You might try some fuel injector /tank cleaner that some time will remove problem varnish on fuel sending unit resistor.

mine is very similar to yours. by the time my low fuel light comes on, i cant put more than 20 gallons, so i have a mysterious 6 gallon black hole. i never really pushed it too far beyond the light coming on since i dont carry spare gas. i think its pretty common for the guages to be way off. i had another chevy before my tahoe and that guage was way off too. i could to 200 miles on the first half of the tank, but only 50 miles on the second half of the tank, atleast according to the guage.

with the GM vehicles I have owned with these 25-26gallon tanks when the fuel guage reads empty I have found 5 gallons still in tank on fill up the amount adds up to the tanks capacity...

this may be a built in design so that vehicle owners do not run down the fuel supply so low that the fuel pump overheats and fails..

If you want to avoid fuel pump replacement do not operate the vehicle below 1/4 .............also replace your fuel filter every 30,ooo mi....

these fuel level indicators are a long time issue ...fuel additives have fouled the resistive pick up in the tank, this is part of the fuel pump...most that still have the original defective pickups use the odometer to keep from running to low on fuel...

with a new fuel pump [delphi] you will no longer have these indicator issues...

Thanks for the replys...mileage is 107000 on the Tahoe. I bought it with 78K and the guage did this from the beginning. Looked like it had been stuck once good in mud, underside by rear end was pretty dirty, so don't know it that had anything to do with the gas tank and guage. I do know gm trucks do tend to have a big reserve, but it bothers me the guage never goes to full. Do the new fuel pumps have the sending guage built in to them?

Thanks for the replys...mileage is 107000 on the Tahoe. I bought it with 78K and the guage did this from the beginning. Looked like it had been stuck once good in mud, underside by rear end was pretty dirty, so don't know it that had anything to do with the gas tank and guage. I do know gm trucks do tend to have a big reserve, but it bothers me the guage never goes to full. Do the new fuel pumps have the sending guage built in to them?

the sender is a part of the fuel pump ..my guage wonders then after a period of driving it will read correctly..I use shell gas...lately it appears to be working better maybe the new formula there using..


when my fuel pump fails the delphi replacement will correct this ..