2006 Yukon XL 2500 6.0L dies/stutters at cruising speed randomly

[jmlhd7]

Drove again today with new scanner hooked up. Sitting at stop lights my tach is pegged at zero and scanner is reading 530-550RPM at warm running temp. The rest of my instrument cluster is working correctly, is there something else that can recalibrate the tach?

 

[Scottydoggs]

Drove again today with new scanner hooked up. Sitting at stop lights my tach is pegged at zero and scanner is reading 530-550RPM at warm running temp. The rest of my instrument cluster is working correctly, is there something else that can recalibrate the tach?

pretty common for the stepper motors in the cluster to fail. that would be my guess. scanners dont lie, that info comes right from the PCM.