My dealer changed the sender unit under warranty. They waited for a while before changing it out, first saying they were waiting for an updated sender unit. This, of course, was years ago, when the car was relatively new. When the "updated" unit was installed....same problem. Somehow, though, the problem disappeared on it's own over a period of time. No empirical evidence, but I think it fixed itself when I switched to Shell gas. Again, I have no reasonable idea why this would eliminate the problem. I use all name brands (but mostly the major brands) of fuel, Shell happened to be the station that was convenient at the time.