I'm attempting to fix a persistent n52 idle vibration. When the rpm's drop after stopping, it will hang at ~800rpm for a few seconds before coming back down to 600. I've smoke-tested the intake and there are no vacuum leaks. There are no engine codes. I've replaced the following (all OE spec):
- Entire engine (spun crankhub)
- Eccentric shaft sensor
- Valvetronic motor
- Throttle Body
- 6x sparkplugs + coils
- All gaskets (Oil pan, VCG, OFHG, TB, intake manifold)
- 2x vanos solenoids
- PCV system
- Engine mounts
- 2x o2 sensors
- 6x injectors
- Crankshaft pos sensor
- Camshaft pos sensor
Any help would be appreciated.