I'm getting a 16486 code pop up a few times recently and after clearing it will not come back for a couple of weeks or so, usually when just pottering around town. Car doesn't seem to be down on power, even when the code is thrown and I can't find any obvious boost leaks - although it looks to all original pipe work so I wouldn't necessarily count one out. It can be bit lumpy on starting sometimes though - not sure if this related, but it never throws any codes in this instance. I'm going to give the MAF a clean and see if that helps, but I obviously won't know for a few weeks given the intermittent nature. Hence I was wondering if this is the normal process for a MAF on the way out or is there another cause I should look into?