Posting this on behalf of a mate. He has a 2010/11 VW Golf diesel. As part of the VW emissions recall he had it done at the local main deal. Straight after the new software update was done he has notice a big drop in economy (at least 15% less mpg) and a drop in performance. He has taken it back to the same dealer and they say all is good and no fault codes.
He has checked online and a few others have the same issues.
So does anyone on here have any ideas? Thanks.