I heard the Z injectors are loud but what type of noise is expected? It happens around 3-4k rpm 2nd and 3rd gear. Sounds like a loose bolt on the heat shield of the manifold. Like a sheet metal vibration. Anyone heard of this and is it normal?

 

Fuel injectors can make a light clicking noise, which is normal. Can you make a video of the noise and post it up because it is really hard to diagnose noises over the internet.

 

a may as well be metal on metal vibration. I have never heard of injector noise sounding like that. more of a tick tick tick.

 

Can you hear the sound inside the car? Is the sound kind of like a helicopter noise?

 

I just had my driver's side cat replaced. The ceramic element broke loose and rattled around, especially when the engine was revved a little. It was very loud and easy to hear.