5.7 hemi problems

I know this is not an A body but need a little guidance. My wife has a 2006 300c with the 5.7 hemi in it that is stock. In the last few weeks when we fill up with gas it starts fine but when we drive it stumbles bad. It bucks 2 or 3 times like it is going to stall and then it drives ok until next fill up. The car has 87,000 miles on it with very little trouble and has been well maintained. I wonder if the fuel pump is getting ready to crap out. Has anybody else had this happen and what is the fix. Thanks Bill