Diagnosis should include
- searching for loose components
- checking for misalignment of components
- listening unaided or with a stethoscope or other sound detector to locate the source of noise
- locating vibrations caused by a misfire or by worn/faulty components
- using a scan tool to isolate misfires.
Process/Skill Questions:
- What tool would the technician use to pinpoint the source of a noise?
- How can engine mount vibrations be tested?
- What would a low, knocking noise indicate?
- What are the differences between high- and low-speed noise/vibrations?