i took it to o'riellys and they said it was the egr valve code when they scanned it, i already bought the egr valve but my problem is i cant get the old one off. i dont know what size wrench it takes, its bigger then a 18mm or 3/4 so i am gussing its a 1 1/16 maybe? this has been such a nightmare for me since i dont know what is going on due to lack of knowledge for mechanics and i just tried to take my car to the guy i got the car from and they didnt have the wrench for it either. i sat waiting for a guy to bring one and i ended up leaving after a hour of waiting. to make things even worst my car runs even shittier then when i brought it in to him so i dont know what they did.