I have a clicking / tapping noise coming from the inlet manifold on my 2002 Citroen Saxo VTR (1.6 8v)
I have manually adjusted the valve clearances (see this video to hear what the engine sounded like before the valve clearance adjustment) however there is a clicking noise which seems to be coming from the inlet manifold from behind the engine.
You can hear the clicking noise in this video. When holding the idle actuator valve I believe I can feel it moving/vibrating at the same speed as the clicking sound.
I unplugged the idle actuator valve and ran the car for a few seconds however there was still the clicking noise. I have read some posts on Saxo forums which mention a similar sound, saying it could be the injectors.