Could this,on mine, be in a hole covered by a reular-head screww? There is this like 1/3 inch regular head screww in that approximate location, which I thought had beent he air mass sensor adjustment screww. It is screwed all the way flush, but it easily screwws coutnerclockwise. I've never screwed it all out. Is this them one that should be removed and then allen screww will be below it?