go back to standard and modify that

http://www.corsasport.co.uk/board/viewthread.php?tid=73970

engine mangement light came lost loads of power aswell so was told to check baffels in exhaust as its knows to be a common fault for them to collapse so checked and they had so bought a jap can and took cat and rear silencer off aswell so done that all fixed then next day the light came on again wouldent start smell petril so me m8 says try putting standard filter back on i laughed and said that wouldent work but i tryed and that has solved the problem now so has any1 else had this problem and is there a filter i can buy for me 1.2 corsa that will work