Truck is a '99 silvo w/ 5.3. When truck is cold you need to prime the pump, then wait a sec then start it. However, if u shut it off and restart it 20 mins later it'll start up with one turn, if it's cold (sits overnight) and you hop in and turn the key to start it it will crank for a while, sputter then start or if u prime it, wait a min it'll start up. Truck has a new pump n filter. Any ideas I can look at next?? Thanks