Audi Diesel 2.0 engine rattle on start up for about 10 seconds

[Neeru247]

Hi, for the last week, on engine start of my Audi A4 2.0 TDI, there is a rattling noise (similar to the noise a diesel engine makes but louder) followed by a pause and then the rattle again. This only occurs for about 10 seconds and then it's fine. I'm worried there may be a deeper problem to come if I don't sort out soon! Thanks!

[cazzz1975]

does the rattle go up and down with the revs?

is it a rattle or a knock?

[TWR]

cam followers.

[cazzz1975]

do you think the cam followers would charge, discharge then recharge again then have no problem?

[Neeru247]

It's more of a rattle but it results in a small shudder of the whole car. When it happens, the car body moves only ever so slightly. Many thanks for your assistance!

[Neeru247]

I'll check the revs on start up and get back to you shortly cazzz1975!

[chas2008]

when did it last have a fuel filter ?...you would be surprised how much difference this can make..

[cazzz1975]

Do the revs drop low when it shudders?

[Neeru247]

Right, it's idling at 1100 rpm at the mo and normally it's at 800rpm. As it rattles, the rpm increases slightly. After a minute, when the engine has warmed up, the rattling stops. A friend believes it is the mass airflow meter. It's almost like I am revving the engine every few seconds by pressing down on the accelerator.