Fuel gauge problem

I have a 2000 Venture and the fuel guage goes where ever it wants to. You can fill up the tank and it might read empty of 1/2 , you will never know. Some times when its empty it reads full tank. I thought it might be a connection but I took them all apart and all connections are good. any Ideas? I am not sure if I should buy a new guage or sending unit.

Thanks
Bill

I suspect wiring or ECM in this case. These units have had their share of problems, including software. Ray

I have the same exact problem with my 2000 venture... haven't figured it out yet.. I just try ot keep track of mileage and fill up when i have a haf tank