i know this subject has been beaten to death but i still need some guidance on this issues. i picked up this 09 Malibu recently it has high mileage plus had those codes, so i figured id go ahead and do the timing chain and guides, i noticed right away that somthing was off the top timing marks on the cam gears had the markings on the chain 1 tooth forward on both, and the mark on the chain at the bottom was lined up with the mark on the block, not the dot on the bottom gear. i will attach photos, this being my first timing job i was to afraid to change it so installed the new chain exactly the same way as it was. I WILL ADD the car runs perfect. sounds great, only issue is the codes, should i dig back in ? or let it ride? the bottom link is lined up with the 2 red lines, it doesn't look like it is because of the angle