After driving for a while (up to operating temp) and stopping at a light sometimes I feel the truck shudder. It usually only does it once and then is fine. Doesn't do it every time just once in a while. It's nice and sunny today other times it's cold a grey. Is this normal? What could it be?

Maybe a 30 June virus. Mine did it once yesturday while sitting at a light. I check for air in the filter when I got home. Some air did escape when I loosened the bleeder screw. Maybe 1/4 a pump on the priming pump and I had fuel. I closed the bleeder and the test continues. No repeat today.