Hello all, have a problem with my Giulietta QV. Fitted a new downpipe without a cat. Went on the motorway then all of a sudden engine light and no power. Managed to get it home after being safely guided off the motorway by the RAC. Only code that have come up are the p0300 - p0304 codes for all cylinders misfires at various times. What is the cause of this I know the codes are multiple misfires from different cylinders but I can't work out if it's because of the downpipe I fitted messing with fuelling or just the coils or spark plugs. It may just be coincidental that a day after fitting the catless downpipe it goes wrong. Any help would be greatly appreciated.