TM 10-3930-669-20 2-13.  ENGINE SYSTEM TROUBLESHOOTING (CONT). 9.  ENGINE VIBRATES EXCESSIVELY. INITIAL SETUP Tools and Special Tools Equipment Condition Tool Kit, General Mechanic's: Automotive Engine OFF (TM 10-3930-669-10) (Item 1, Appendix B) MAIN POWER switch OFF (TM 10-3930-669-10) Parking brake applied (TM 10-3930-669-10) Wheels chocked (TM 10-3930-669-10) References TM 10-3930-669-10 KNOWN INFO Nothing. POSSIBLE PROBLEMS Engine mounts faulty. Engine supports faulty. TEST OPTIONS Visual inspection. REASON FOR QUESTION If engine mounts are faulty, engine will vibrate excessively. 2-110