2002 Chevy Tahoe Engine knocking when I accelerate up until

My 2002 tahoe is in great condition except for one major issue. The engine is clicking/knocking when I accelerate. It seems to make the noise until I get to a gear around 30 mph. Should I rebuild the engine or is this a simple issue? I don't want to look for a new car but I am thinking six grand to have a engine rebuilt and installed might be the most economical route to take. Any opinions would be greatly appreciated.