hey everyone
sorry to post so soon after joining but im worried about this noise.

i have an 03 350z track. Theres a loud humming/chugging noise that seems to be coming from the engine.

its there as soon as i start the car and is there wen ever its idling. the noise reminds me of a 250cc motorbike struggling to warm up and chugging. but the noise is there when the engine is warm.

there is no clicking noise or clunking.

the cars has done 102,000 and its had its timing chain replaced.

the noice can be heard inside and out side the car. is this normal?
thank you in advance
faisca