ok so here we go bought my 03 gt few months back ran great then cel started flashing 1 day then stopped and shut off days later cel came on for small vacuum leak and a cylinder misfire p300 all cylinders so found out there was a crack in the exhaust manifold so I replaced them with bbk shorts sounds great mind you so everything running good for like a week or 2 then it does it again cel flashing so took it to a shop they said intake manifold so I did it myself today and took it for a ride after and sure enough flashing cel im lost idk what to do please help anyone.....