Here's a picture of the fuel metering unit.



You see that thing at the bas of the sender? That's what actuates the fuel light.

Here's another picture.



See the little holes under it, It's possible some dirt got in there and it's sticking so the light is always on.

That's why I said just drive it and when you get low on fuel again go over some speed bumbs and maybe the problem will fix itself.

Here's a picture of my car with no tank while I put my Walbro 255lph fuel pump in