Suzuki Alto Rough Idle Points to Failing Catalytic System

I experienced similar symptoms with my 2020 Suzuki Swift. The engine light came on repeatedly, accompanied by rough idling and noticeable exhaust fumes. The initial diagnosis revealed a faulty oxygen sensor, which was causing incorrect fuel mixture readings. This triggered the engine light and led to poor combustion. The exhaust leak you mentioned could be from a loose connection or damaged gasket where the oxygen sensor connects to the exhaust system. In my case, the problem escalated when ignored, eventually affecting the catalytic converter due to the improper fuel mixture. The diagnostic showed both front and rear oxygen sensors needed replacement, along with deteriorated sensor wiring. The repair involved: Testing exhaust system for leaks, Replacing both oxygen sensors, Repairing damaged sensor wiring, Performing ECU reset, Checking NOx sensors functionality This was a serious issue requiring immediate attention, as continued driving could have permanently damaged the catalytic converter. The symptoms match what you describe, and I suggest having the oxygen sensors checked first before investigating other components. Getting a proper diagnosis using an OBD scanner specifically checking for exhaust-related codes would be the best first step.

Thanks for sharing your experience. That exhaust malfunction sounds exactly like what I am dealing with. After reading about your oxygen sensor issues, I realize I should address this quickly before risking catalytic converter damage too. Did you remember roughly how much you ended up paying for all those repairs? Also, has everything been running smoothly since the fix, or have you noticed any other problems pop up?

Thanks for asking about the repair costs and follow-up. The exhaust treatment malfunction is completely resolved now. A bad Lambda sensor was causing the main issues, and replacing it cost 375€ including labor and parts. Since fixing the oxygen sensor three months ago, the engine light has stayed off and the rough running is gone. The exhaust pipe is functioning normally with no leaks or odd smells. No other problems have emerged, the engine runs smoothly and fuel economy is back to normal. Getting it fixed quickly was definitely the right call. When these sensors malfunction, they can lead to expensive catalytic converter damage if ignored. The repair shop did a thorough check of the entire exhaust system to ensure there were no other developing issues.

I finally got the issue resolved at the repair shop last week. Based on everyone's advice, I had them focus on checking the oxygen sensors first. Turns out my problem was similar, a failed sensor was causing the rough running and engine light warnings. The total repair came to 420€, which included: New oxygen sensor, Gasket replacement, Labor costs, Computer system reset The catalytic converter thankfully showed no damage when they tested it. The exhaust leak was just from a loose connection where the old sensor had worked itself free over time. After a week of driving, the engine light has stayed off and it runs perfectly smooth again. No more exhaust smell or rough idle. Really glad I caught this before it led to bigger problems with the catalytic converter or other exhaust components. Thanks for helping point me in the right direction with the diagnosis. Getting it fixed promptly definitely saved me from more expensive repairs down the road.