01-05 Saturn 3.0 L, L81, (JB) and 02-03 Saturn VUE ( Z5 , Z6 ) Pop Noise from Engine Area during Heavy Throttle Input - kw clunk intake manifold accelerate pedal

The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.

Pop noise heard from the engine compartment, intake manifold area, during heavy acceleration or in park/neutral with heavy throttle input (normal condition).

Intake plenum switchover valves are actuating under heavy throttle input. This condition is heard more from a VUE than L-Series. The noise can be heard from both car lines. The VUE may be louder due to six flappers actuated by two vacuum motors close to the intake runners inside the upper intake manifold. The L-Series has a plate in the back of the upper intake manifold that rotates 90 degrees. To identify if the noise is from the intake manifold, disconnect the electrical connections to the vacuum chamber switchover valves and note if the noise is eliminated. If the noise is eliminated, the condition is normal and no repairs should be attempted.

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Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance.

(00, 01, 02, 03, 04, 05 Saturn L-Series L81) and (02, 03 Saturn VUE L81)

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