Dude i went through this before read my.thread. If your vacuum lines, spark plugs, coil and fuel filter and injectors are ok then it's your main catalytic converter the one underneath the car at the middle section. Depending on which state you are located and if they don't have emissions laws just go to a muffler shop and tell them to cut it out and replace it with straight pipe. If you have any questions just call me. My name is Stephen and located in Miami FL. This cars are nice but you have to be Patience with it and have basic mechanical knowledge or else mechanics will just take you for a fool barely any mechanics know or ever worked on this car before.