This Preliminary Information communication provides information to the technician about vehicles that have a vibration that is felt between 1200 ? 1400 engine revolutions per minute when in active fuel management V4 mode. Technician will need to use J?38792-A Electronic Vibration Analyzer 2 or CH?51450-NVH Pico Oscilloscope Diagnostic Kit to measure the frequency of the vibration. Technician will need to remove and replace the exhaust muffler clamp that joins the three-way catalytic converter assembly to the pipe of the muffler assembly. After the exhaust is reinstalled remove and reinstall each cab mounts and retest.
