How many miles are it? Does it do it all the time or is it worse when it is cold? The reason I ask is because my truck (1999, 5.3) started with a rough idle when it was cold, and continued to get worse over time and run rough when warm. Got lean codes, misfire bank 1 & 2 codes, yada, yada, yada. Finally narrowed it down to the intake gasket. Super easy to replace. Good luck tracking down the problem.
