Lexus LFA NOx Catalyst Aging and Exhaust Leak

Interesting. I had a similar issue with my LFA. By NOx catalyst aging, do you mean a fault code related to nitrogen oxides emissions? The exhaust leak could definitely be the culprit. An exhaust leak messes with the oxygen sensors, which then affects the whole emissions system and fuel efficiency.

Yes, the fault code specifically references nitrogen oxides. The exhaust leak is my primary suspect as well. Did you happen to find the exact location of your leak?

I didn't pinpoint it myself. I took it to a workshop. They found a crack in the exhaust manifold, which was causing the leak and triggering the NOx issue. I would advise getting it checked professionally to avoid further damage to the emissions system.

Thanks for the info. Confirmed the exhaust leak at the manifold. Repair cost was 265€. Replaced the gasket and the check engine light is off. Appreciate the help.