I have a JDM ZC and transmission out of a 93 del sol si. The swap was ok and after it was done the car ran just fine. 2 weeks later it starts bogging down. It wasn't making the straight flow sound through my Greddy t-183 muffler instead it made the sound of a harley or gt mustang at idle. I lifted the car and noticed the catalytic converter was burned. So i chopped that off and placed a 3 inch pipe from the headers to a glasspack to my muffler. The car still bogged down even after the cat which needed to be replaced was cut. I noticed that wires from the O2 sensor in the headers had come disconnected. I reconnected the wires to their correct location but accidently broke the wires off in my Coolant Temperature Connector. After replacing that the car runs ruff at idle and still bogs down. So my question is and any help will do. Could it be that my timing is off or the o2 sensor by the cat is telling the computer theres a problem. If anyone has had this problem and got it fixed please tell me or if you have an answer let me know. Thanks