THIS PRELIMINARY INFORMATION COMMUNICATION PROVIDES INFORMATION TO THE TECHNICIAN THE STEPS NEEDED TO DIAGNOSE AND REPAIR VEHICLES WITH A ROUGH IDLE AND/OR VIBRATION AT IDLE IN DRIVE. THIS CONDITION WILL NOT BE PRESENT IN PARK, OR NEUTRAL. THIS CONCERN MAY BE CAUSED BY GROUND OUT WITHIN THE ONE OR BOTH ENGINE MOUNTS. TECHNICIAN WILL USE CH-51450-A (PICO OSCILLOSCOPE) TO MEASURE THE VIBRATION DISTURBANCE. IF THE VIBRATION CONCERN IS E1.5 IN THE HORIZONTAL / LATERAL DIRECTION WITH PICO SENSOR MOUNTED IN SEAT TRACK AS INDICATED – CONTINUE WITH STEPS TO REDUCE THE AMPLITUDE OF THE VIBRATION BY ADDING SPACERS IN KEY LOCATIONS TO REDUCE GROUND OUT WITHIN THE ENGINE MOUNTS. THE 6.2L ENGINE HAS A CHARACTERISTIC E1 WHICH CAN BE FELT, AND MAY BE DESCRIBED AS A LOPEY IDLE. DO NOT CONFUSE 6.2L E1 CHARACTERISTIC (NOT CAUSED BY MOUNT GROUND-OUT), WITH E1.5 NORMAL IDLE CHARACTERISTICS BEING TRANSMITTED INTO THE TRUCK VIA GROUND-OUT THRU THE ENGINE MOUNTS.
