I filled my car completely up with gas a few days ago. Ive drove about 125 miles since then, but the gas gauge thing is still on full. Could this be possible, or is my gauge totally screwed up? I've never had issues with it before.
Is this something that can be fixed, and is it expensive to fix?

 

Howdy Pumpkin
Without looking at your car, to see for myself, I would have to say that it is a calabration issue. I've owned some cars that you fill it up and it will go a few days and stay on full then head for empty once the needle comes off the full mark. On the other hand I've had them where they would come off of the full mark quite quickly but you could drive a long way with the needle on empty. As long as it is working I would not be concerned. What I would do is set your trip meter and note when you fill up how much gas it took, how many miles you have driven and how many gallons you have left in your tank. This will atleast let you know how many gallons you have left before you run out. Hope this helps. MC

 

It could be a sticky gauge or sticky sending unit. If it is the gauge you will have to replace the complete gauge cluster, if it is the sending unit you will have to take the gas tank down. You can check the sending unit if you have a repair manual and a mutimeter. It should have a some resitence in the wires, how much will depend on how much gas you have in the tank, I would suggest you try at where it is (you can guess how much you have) then try again after you fill it up. You will have to find the wires off the sending unit at the tank to do this. If you take it to a shop it shouldn't take them long to figure it out. You could also have a bad ground. I haven't tried this on a newer car yet but if you turn the key on and disconnect the ground off the gauge, I would do it at the sending unit, it should drop to E, if you touch that to a ground (frame/body) it should jump to full. Just make sure you find a good ground when you do it.
Good Luck.

 

Have fun replacing that sending unit. $400~ bucks.