I know in Bonne's ..not sure on GP's, but from 97 to 98 they changed the resistance on the senders. 97 was like 0-90ohms and 98+ was something around 0-250ohms. Apparently this kept the gauges from having quick swings etc.

Bring a flat screwdriver that can take a beating, a pair of needle nose pliers, 10mm socket/wrench/nutdriver, hammer and a pair of circlip pliers. If you don't have the cirslips..don't worry.. you can pry the clip out. There's a couple different ways the sender is held into the car.