Recently my 4 runner gauge will ready empty with the light on even though it has gas in it. Level does not matter. I did hit the mode button just to see and it read like it should so, think the gauge is the problem? It comes and goes. Need some input please.

2008 4 runner limited V-6 2 wheel drive

Likely an issue with the level sender and not the gauge itself.
The sender is part of the fuel pump assembly. PN is 7702035112

As @UrbanRunner651 stated, this is typically the fuel sending unit. This comparison shows what eventually happens: the "track" where the float arm moves wears away over time. Bottom pic is my part after removal.





My post about this repair may be helpful.

Yep, agree that its the fuel sender unit. I had the same symptoms.

Unfortunately, its in the gas tank. Plan to replace at least the fuel pump while you are in there. Its not an awful project, but it does take some time. You will want to run the gas tank down as low as you can with a stuck gauge. Mine decided to start working as soon as I had it down to 1/8 of a tank, but I went ahead and replaced it anyway.

If I read your post correctly, when you hit the "mode" button all the info is correct for the amount of gas you have in the tank, if so that tells me the fuel sending unit in the tank must be working correctly, so the issue is in the gauge itself....so my guess is the "stepper" motor, which there are 4 of on the instrument cluster circuit board, one for each gauge in the cluster, has gone bad, they can be replaced but they are soldered on the circuit board, if this is the issue you have 3 options, replace the motor/s yourself, send your cluster in too a specialty shop that does this kind of work to have them do the repair....or get a new/reman/used cluster from the aforementioned specialty shop, or savage yard which has to be for your exact year and model T4R.

Here's a link to a topic on the stepper motors subject.

Dashboard gauge needles not working or showing incorrectly -- FIX

The next link is too a site for buying new stepper motors, a rebuilt cluster or having your's rebuilt.

The owner of this site is also member here @TaninAuto and has posted a discount code that may still work for 10% off....

"We have a discount code for the 4Runner forum, you guys get 10% off with code "4RUNNER10"

You searched for - Tanin Auto Electronix

FWIW, my range readout did not change other than steadily declining over time to where I would fill up and it would read 320 miles instead of the usual 370-400 before. I've often wondered where the range and mpg numbers even come from. Range is typically close as to when the needle reaches E, though I believe it's calibrated to use ~20 gallons in the calculation so as to provide a reserve. I can drive 60 miles or so after reaching E and seeing the fuel light, probably farther though I don't care to test the limit. The average mpg figure though has always been ridiculously high compared to accurate, hand-calculated figures based on miles traveled divided by gallons to fill. Bottom line being that with respect to @AuSeeker I still lean toward the fuel sending unit based on the symptoms and the fact that the mechanic I use said it's almost never the gauge.

Thank you all for the quick reply. I was feeling like I am to the point of replacing the fuel pump and sending unit. Did not think about the stepper motors. Same issue on my 07 Duramax. I know exactly what your talking about.