2001 Jetta GLS 1.8T Misfiring with P0300-P0304 and P0172/P0118 Codes
My 2001 Jetta GLS 1.8T is experiencing multiple misfire codes: P0300, P0301, P0302, P0303, and P0304 (all cylinders affected), along with P0172 (System Too Rich) and P0118 (Engine Coolant Temperature Circuit High Input). The vehicle lacks power and emits a strong exhaust odor from the catalytic converter area. Although I've previously replaced ignition coils, they are not the current issue. Based on research, I believe the problem may be a faulty catalytic converter. Unburned fuel during misfires can damage the catalyst, leading to reduced performance and exhaust smell. I'm seeking confirmation on whether a failing cat converter can cause widespread engine misfiring.
Try removing the oxygen sensors or the catalytic converter to see if engine power returns—this can help determine if the converter is causing the misfire.