Rocker arm tap

2003, s-10, 4.3, vortex, 19,000 miles, use best oil, change every 3,000 miles. I hear what seems to be a valve tapping.....Any ideas, and is anyone having problems with this engine? My last S-10 Blazer went 135,000 miles without any valves tapping! I will call the dealer, but I was just wondering if I was the only one with this trouble. Andy