2008 BMW 328i: Engine ticking & sounding like it wants to stall

As George suggested, check for fault codes if you can.

In my own opinion, this noise could sound like hydraulic followers ticking or another camshaft related component noise, but to be sure, you could use a strobe light synchronized with your engine, to identify the frequency of the noise, if it happens at every revolution, it's probably a crankshaft related noise, if it happens every two revolutions of the cranckshaft, it's probably a camshaft related noise.

If you don't have such tools (I do not have such tools), you could drive the car downhill (if there are hills around you, else try on the flat) engine braking, or shutting the engine off, just to see if it stops when there is no explosion, if it stops, the noise probably come from a crankshaft related component (crankshaft bearings, connecting rod bearings, piston pins)... (I hope it doesn't), it could mean there is clearance between some crankshaft or pistons related components and the explosion in the cylinder pushes one of these components against the other because of this clearance, making a knocking sound.

If you can still hear the noise without explosion, it's certainly caused by the camshafts or the valvetrains, it could be failing followers (I assume yours are hydraulic), or bent valves that are not closing correctly for instance, increasing the valve clearance and making the cams knock.

Hope it helps.