Who ever wrote the timing procedure should be shot : r/Justrolledintotheshop
GM 3.6 with just a tad over 60,000 miles. Was running in limp mode. Timing chains need to be replaced since they're stretched : r/Justrolledintotheshop
How To Replace Timing Chain On Chevy / GM 3.6L V6 - Full Length Removal and Install - With Tips! - YouTube