1998 Chevy 1500 4 WD 150,000

The fuel pump was replaced about 15000 miles ago. My question involves stalling when the truck is cold. I will start the truck and it idles fine. When I put it in gear and move 100' to 500' it dies. It will restart but acts like it isn't getting fuel, so I have to keep my foot on the gas for about a minute until it warms up a bit. After the first minute or so it will run great. The one thing that has me puzzled is that when it dies the clock on the radio has to be reset, like the electical system is shutting it down. Do you have any idea what may be causing this.