Slowly loses power

I have a 2003 Bonneville 6 cyl. that's at the dealer right now. Twice
in the past three weeks it lost power and shut off (over about 15
seconds or so). Restarts right away, no problem. The dealer said
there are no codes showing up. I am getting oil change, they said the
fuel filter was very dirty. Also needed brakes. I noticed that I
always have the cruise control on when it happens. First time the Low
Trac light came on, and it was raining outside. I do not have the
Traction Control button in my car, it is an option I didn't have on
mine. I've also read it could be a fuel pump problem. Any ideas?