matssky66
Lexus LFA Exhaust Leak Rough Running
Summary of the thread
A 2012 Lexus LFA is experiencing a check engine light, rough running, and an exhaust smell, suggesting a potential exhaust leak. Possible causes include a defective lambda sensor or issues with the catalytic converter or particulate filter. A professional diagnosis confirmed a defective lambda sensor and a small crack in the exhaust manifold gasket, both contributing to the problem. Repairing these issues resolved the symptoms.
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4 comment(s)
matssky66 (community.author)
No recent exhaust work. Fuel consumption seems normal. Could a bad lambda sensor cause an exhaust leak, or are these separate issues?
GBeckRider
A lambda sensor monitors exhaust gases, but a severe malfunction could cause combustion inefficiencies, increasing back pressure and worsening a weak spot in the exhaust system. The exhaust leak is probably separate, maybe a crack or failing gasket. Get a professional diagnosis to pinpoint the source before replacing parts.
matssky66 (community.author)
I took it to a shop, and they confirmed a defective lambda sensor and a small crack in the exhaust manifold gasket causing the leak. The total repair was 375€ for parts and labor. Thanks for the help.
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LEXUS
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LFA
GBeckRider
Check engine light, rough running, exhaust leak, and smell points to a defective lambda sensor. Has the exhaust system had any recent work? Any change in fuel consumption? A faulty oxygen sensor affects the catalytic converter, but we need more data.