Is it my fuel pump?

had brother in law change my fuel pump, filter, and spark plugs. so now my problem is when i hit about 60- 70mph i can feel my truck sputter a little, mostly when i gas it just a little over a hill or when cruise controll does it for me. its starting to get worst. could my bro. in law made an error w/the fuel pump? or does anyone think it might be something else? 98' chevrolet z71