Hi jamie i know it was a while ago but how did you get on with the astra you had in back in april with the misfire and showing code p0300 p0303. Would be intrested to haer your fix for it as we have got a corsa in with the same fault codes. i know the vauxhalls do suffer with misfire problems as we had one that would shut down injector 3 it turned out to be the ecu. Thanks Steve