my wife has a 2001 tahoe with a 5.3. when you get just below a 1/4 of a tank, it surges real bad mainly on grades and under power. once you fill up, it runs fine. it just started about 10 tanks ago and doesnt get worse yet. i am thinking it is the sock in the tank halfway plugged up, but not sure. tell me what you guys think. all help is appreciated
thanks, luke