Fuel Gauge Macarana?

[75BeauJames]

I've got a slight problem that's been annoying me, and the more I drive it, the worse it annoy's me!

With the engine stopped and the key in the on position, the fuel gauge reports the fuel, and seems to be accurate. However, as soon as it starts up, the fuel gauge does the macarana! It flops around anywhere between 1/4 and a 1/2 of play. (I.E. if the tank is 100% full, it will bounce anywhere between a full tank and a half tank). It never seems to go higher than accurate (i.e. half tank will bounce between a half tank and empty and not back towards full), but definatley goes under.

Someone at work suggested that I'm loosing a ground somewhere, and suggested I take a meter and read the ohms/voltage on the sender leads on the tank, and again at the dash gauage. Someone else suggested I just replace the float for the fuel sensor...

What do you guys think?

Scott