The past few, actually, several times that I've filled my SC2 up with gas, I've put the pump in, and let it go. Then when it automatically stops, I take it out, pay and leave. Normal, right? Well, I discover as I'm driving away that the automatic stop doesn't completely fill up my gas tank. For example, the last time I filled up a few days ago, I had about an 1/8th of a tank left and when I filled up, I was bumped up to 3/4's. This has happened several times at different BP stations in town and while it doesn't happen all the time, 8 out of 10 times it does.

Is this phenomena my car or BP's faulty gas pumps?

Any answer would be appreciated - Thanks!