Hi, I think you mean that you have removed the "CAT" and since then it will not run correctly, well if thats correct I'm not supprised as the engine's ecu is designed to work with the "CAT" and if you get pulled over for a roadside check your car if it was running would fail the emision tests and you would have to fit the "CAT" back, did you also delete the Lambda sensor?
nigel
June 2008