Vinnymac16

Hey all, I just bought an 08 Sliverado crew cab Z71 with the 5.3 and 37k on it. It was fine when i test drove it but I've put about 125 miles on it and I've noticed some surging under normal acceleration when pulling away from a stop up to about 45 mph. It's not like anything is slipping but more like a fuel or spark problem. It's not throwing any codes. I'm an old school wrench turner but have no idea