Hello. I have a 2004 Suburban with a 5.3 Z VIN and 190K. I suspect that I have a bad lifter or rocker due to a non-belt related "chirp/squeak" that is tied with RPM. What is the best method to identify which cylinder/lifter is causing the problem before tearing into the valvetrain and no longer being able to run the motor? Thank you

 

have you removed the belt and ran the engine to see if the noise is gone? I've seen camshafts make a pretty bad squeak type noise but all in AFM engines which yours is not