I'm not trying to play devil's advocate fillyman, but it's common sense by drilling a hole is just temporary solving the issue without extensive testing to prove it's a full time cure
The stock exhaust on all Brera's hampers the cars performace in my view, an upgrade would be the right thing to do with some fuel pressure adjustment in the ecu.
Not meaning to sound rude, but if people want to follow what someone says who they have never met on an internet forum and drill a hole in their backboxes without consulting an exhaust technician before hand, they only have themselves to blame.
I was only trying to give a second look at what could be a bigger issue.
I would try Alfatune in St Helens for advice if i had the 2.2 with the issue or even try the Vauxhall forums to see what they all say, there's alot of Vauxhall's & Saab owners that may shed some more light on the issue.
Last edited by IAMBRERA; 02-11-14 at 18:11.