I've got an irritating'noise coming from the top of the engine, at the back somewhere. Worse under load, almost disappears on the overrun.
To me it sounds like the exhaust - it's not.
A little blow at thye manifold? Can't find one, nipped all the bolts up - no change.
A couple of mechanics have heard it and instantly said 'leaky injector' - checked that all are tight - no sign of a leak.
I suppose it could be 'chuffing' out of the head gasket at the back, but it runs the same as ever, and I'd have expected it to be constant.
Is running lean according to the mot test - which could point to an injector again, but is running at the same temp etc as always.
Suggestions before I start buying bits to try at random?