2001 Malibu Gas Gauge.

I filled up my tank this morning and as I was pulling out of the station, my gas gauge fell to empty. It stayed like that until I got to the highway, and then it slowly increased to full. What gives?

Well, Not the same but my does the same I have like half tank fill it up until the pump clicks then I get in the car start it and slow it goes to the full

When I had a similar problem with my 99 malibu it was the sending unit for the fuel guage. Unfortunately the sending unit on at least the 99 is a part of the fuel pump which is rather expensive. I therefore just used my odometer to determine how far I could go before I needed to fill up. I was able to do that for maybe 10,000 miles and then the fuel pump went as well. When they replaced the fuel pump that automatically replaced the sending unit and the gas guage was happy again.

The fuel pump went out for me at about 130,000 which I think is about right. If you're close to that you might want to just replace it when it's convenient so that you don't have to replace it when it's not convenient.