Sounds like a dodgy sensor to me. The tappetts will rattle until they get coated in gunk again - some slick 50 or X1 superlube will help keep the rattle down.
I would unplug and replug everything in again including air feed pipes just to be on the safe side. The buzzing noise implies a short across a relay or switch. Keep revs to below 3000 for the first 300 miles while you are bedding things in - I'm assuming the bottom end and engine below the head gasket are not touched.
There could be an oil pressure issue as well - you really should keep an eye on the oil pressure with a gauge. |