During the last 10 to 15 years, vehicle design and engineering have dramatically changed because of increased fuel costs, decreased fuel supplies, Corporate Average Fuel Economy requirements, clean air legislation, foreign competition, crashworthiness, and rising customer expectations. Vehicle designs have evolved from full-frame construction, utilizing multiple noise/vibration isolating body mounts, to lighter unibody designs that transfer noise and vibration much more readily.

General Motors has greatly reduced the use of heavier and smoother running V8 engines, replacing them with lighter, more fuel-efficient engines. During this same period, options such as air conditioning, power steering, and have become more and more popular. These types of options increase engine load. They can also generate unwanted noise and vibration.

Customer perception of quality can be directly linked to the presence or absence of unwanted noise and vibration. A technician's ability to quickly diagnose and repair a noise or vibration directly affects that customer's loyalty to the dealership. Technicians who are capable of satisfying this need will be highly regarded and in great demand.

The intent of this section of the service manual is to provide a systematic approach to vehicle vibration diagnosis and correction. By using Strategy Based Diagnosis and troubleshooting philosophies covered in this section, technicians will be able to provide effective and timely repairs.