Hi - I drove my Audi to the shops today and, just as I came to a stop, I heard a clanking sound from teh rear passanger side.  I drove the car on a 300-metre round trip at low speed, and couldn't hear the sound again.

 

When I've come back to the car, the accelerator seems very spongy, and there is virtually no power.  The car will not rev past 2,000 on the move, meaning that I can only (very gradually) get it to around 60mph.  There are no warning lights, and I can't see any evidence of anything wrong.

 

I'm told that there is something called 'limp mode' which the engine mangement system may have initiated if it sensed something wrong - if so, why are there no warning lights on?

 

Would appreciate any insight/thoughts anyone could give?

 

Cheers

 

Chris

 

 

If the knock was defiantly at the rear of the car, I would not suspect it is relevant to the problem.  Your car may be in limp mode for a few reasons but it can take a few ignition cycles to recognise it is a permanent fault and illuminate the EML.  The cause of that engine going into limp mode (or a lack of power) would normally be either a fault with the vacuum unit or stop screw on the turbocharger, or a fault with the DPF system.  Other things to look for are leaking boost system components.  Is your car not still in warranty?

 

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