I replaced the fuel filter, removed both batteries and had them tested, replaced the air filter assembly with a K&N FIPK, and it still does not want to start. And, the "Service Engine Soon" light still comes on when you depress the accelerator right before the turbo spools up. And when you are in 5th gear and doing about 40-45 and you let off the accelerator, you can hear a thumping noise; it goes away when you depress the accelerator again. On top of all that, it is a dog until you get up to around 2K rpm and the turbo really kicks in. The cat has been removed, so it is not blocked there. Any suggestions?