Last week I noticed an engine knock after warm and only at idle to fast idle 1700rpms. This a 2005 Infiniti G35 6MT. I am aware of the noiisy Dual Mass Flywheel issues but this is different. With the clutch deppressed or released the knock can be heard. It sounds like its comming from the rear of the engine towards the top but could be lower.33k miles. Any ideas?