It sounds like a lot has been happening in the timing department and this is just a guess but it still sounds like the timing is out of whack to me. It's not uncommon to have no per-ignition when stationary revving with no load, but around 3000 rpm under load a knock would be unsurprising, especially if the noise goes when you back off. A loose chain would tend to rattle all the time. I'd dump the tune mod (temporarily) if possible and go back to a defined stock start point and re-time the engine and get it running right. If you still have a rattle then you can chase the problem elsewhere. I see you have essentially done that (maybe twice), and given that you have no rattle on stock settings, then it's looking like a crook map to me.
As a partly unrelated issue, if it is coming from RHS on the engine (as seen from drivers seat), then the air-con tensioner idler pulley bearing can fail and make quite a rattle too, although this seems unlikey in this scenario.
Last edited by Doug_MPS6; 26-03-2013 at 02:46 PM.
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