Fuel gauge has a mind of it's own

[Travisbsmith]

I recently put intake gaskets on my 1996 Tahoe. Ever since then my fuel gauge is on the glitch. I did put a new alternator on it, as well as a 4 gauge body ground from the battery.I didn't know if the new alternator would "back feed" or if it was a higher amperage than I should have. Any input is appreciated thanks