I had a new alternator put in my 98 Malibu on Monday and the fuel gauge is now off. It reads "fast", as in a clock or watch: it shows more than exists. When the tank is full it shows full for a while before starting to go down. When it reads about 1/8 of a tank left, it is about where it should ding and the light go on.

Is the gauge problem related to the new alternator or just a coincidence?

Can I fix it myself? Unfortunately I had the alternator replaced about 1000 miles from home since we were traveling.

Woodpecker

Common problem, google for the easy repair, can't remember all it entails.