Cold start idle 'rough'

[KieranJ22]

Evening, I have a 2013 a3 8v 1,8 stronic (17k miles) which is stock other than a pedal box and a cat back exhaust (pipe was cut betweenthe middle silencer and cat. This exhaust mod was done just before christmas but since the past 2 weeks the car has been quite 'rough' and 'shaky' during cold starts. Could the weather or the exhaust be a reason for this? or something else? any help appreciated..

 

[micloi]

First thing i recommend doing is checking with vcds for misfires or similar errors.

 

[Matt Titanium]

I had this with my 8v 1.8 at around 20k. Has it ever not started straight away or ran on three cylinders for a few seconds when it has started? I could feel the idle was bit rough and not quite right even when it did start ok.