Fuel gauge we don't know how much gas is in the tank. car runs good. but gauge does not read correctly. is there any way to check the gauge and or the pump? can you give some advice? thank you. run-out-of-gas

Is this a flex fuel vehicle. If so, call the dealership and ask the parts dept. if there is a gauge module (perhaps behind the instrument cluster). This may be the culprit and needs to be replaced.

when the tank is full the resistance is low so the power through the gage make is read full
as the tank empties , the resistance increases so the less current means the gauge reads less until empty there is little or no power , the gauge reads empty
simple check , turn the ignition off, no power , no gauge reading

float may be stuck up;Take tank unit out and check it with power on and observe the travel and relative gauge position.

I have seen this kind of problem before. You will have to get access to the fuel pump. Some cars have an access under the rear seat. Most don't, so you will have to lower/remove the fuel tank and the locking ring on the tank that secures the fuel pump/sending unit. You may see obvious signs of a problem, like a hose loose, but i recommend that you replace the fuel pump/sending unit even if you don't see a problem.

if the check engine light is on then there is a code set in the ecm(computer) that you need to have pulled and diagnoised.if your spraying starter fluid and it starts then you have a fuel delivery problem,could it be out of gas,plugged fuel filter,bad fuel pump,injectors not being comanded to open by the ecm.this should help to get it running,

Hello and welcome to FixYa!
As a first course of action, please do check the fuse. If the fuse is blown, the fuel gauge won't work. If that's the case, please replace it.
If the fuse if good then the problem will be on the fuel float itself. The fuel float is located above the fuel tank. You will need to pull down the fuel tank to gain access to the fuel float. Once replaced, the fuel gauge will work normally again.
Hope this helps and thank you for using FixYa! Have a good one!

very well sounds like the sending unit in the tank. Try running some octane booster and fuel injection cleaner in tank of the truck to loosen any deposits on the float.

You have a bad fuel level sensor.The fuel tank needs to come out and the sensor replaced.You don`t have to replace the pump assembly.You can get the level sensor separate.I`m not sure if the parts stores have it but I know the dealerships do.Hope this helps.Good luck.

Is......the problem--"the gas gage reads empty when there is fuel in the tank. OR, The gage moves when the key to turned off ?

If it's the first,
You will need to test the gage and through process of elimination, determin if the Sending unit inside the fuel tank has gone Bad.

If its the second ? - Electrical gauges will move when powered down. Normal

Testing the gauge may not be easy - just depends on your ability.
It is a simple 2-wire gauge circuit, when disconnect (usually need the fuel tank) the gage reads in one direction (either full or empty)
then when shorted-the gage reads in oppisite direction.

Of course you must select the correct wires or you may short out the wrong circuits!! Most GM vehicles use a purple wire & black wire.

A quick method I have used to check the in-take part of the gauge is this.
1st. know there is gas - 1/2 tank works best.
2nd driver's door open, key in run position, engine not running.
3rd gently lift up on the door then let if come back down, gently.
just enough to cause the gas to slosh around.
4th - keep an eye on the gas gage, a bad sending unit in the take will show up as a "twitchy" needle.

Of course, if the gage never leaves empty - sloshing won't work.
I have a known good sending unit I can plug into the vehicle and simulate different levels of fuel - if the gas gage works, I know the problem is in the tank.

Let us know.

Dave

defective or missinstalled fuel pump would be my first guess.