LFA Running Rich

Those symptoms point to a potential issue with your air-fuel ratio, possibly caused by a faulty injector. It's like trying to bake a cake with too much sugar; the result is never quite right. Has the catalytic converter been checked? Also, have you inspected the oxygen sensor or the intake manifold for any signs of issues?

Regarding the catalytic converter and oxygen sensor, is there a straightforward way to check these myself, or would specialized diagnostic equipment be required?

While a visual inspection might reveal obvious damage, a proper diagnosis of the catalytic converter and oxygen sensor often requires diagnostic tools. The symptoms strongly suggest a fuel delivery problem, and a defective injector is a prime suspect. I'd recommend taking it to a qualified workshop for a thorough inspection to confirm the injector issue. It's better to be safe than sorry, especially with an LFA.

I appreciate the advice. I took the vehicle to a workshop, and the diagnosis confirmed a defective fuel injector. The repair, including parts and labor, amounted to 515€. Thank you for pointing me in the right direction.