“I can go from zero to studying”
Rory quips that she can go from “zero to studying in less than sixty seconds”.
This is a riff on the term “zero to sixty”, meaning to accelerate from a standstill to sixty miles per hour. It’s used to indicate how quickly a vehicle can accelerate, and is often used more generally to indicate a rapid movement of some kind.
“Grind it till you find it”
Gypsy calls Jackson “Mr Grind-it-till-you-find-it” when she’s fixing his truck and finds the transmission is damaged.
This phrase “grind it till you find it” is used derisively to describe people who grind the gear stick while shifting gears in a manual vehicle, trying to find the correct gear. It does indeed ruin the transmission.
The Annotated Gilmore Girls 