Evening all, looking for a little help. My 3.2 on an 04 has a strange rev counter issue, between 1800 and 2500rpm when cruising it bounces slightly, about 100rpm of movement. It only does it when cruising. The car has had the ecu software update and this made the range in which it does it greater, it only did it between 1800 and 2000rpm before. Coil packs and plugs changed, all earthing points in the bay cleaned with no error codes stored. Any thoughts what it could be?