bbss8

Good day,
My 01 S8 gets lethargic and feels relatively powerless in warmer weather. Also, I think I'm hearing some pinging at the same time. Is there a common temp sensor that needs replacement on these? The car is very powerful below 65 degrees F. Thx.

silverd2

Is the check engine light on?

Have you run a VagCom scan? ...or at least a free parts store code scan (only reads engine module)?

The most common failure is the double coolant temp sensor behind the engine, mounted on top of coolant pipe there. Half the sensor sends a signal to your coolant gauge...the other half sends a separate and independent signal to the ECM to adjust fuel mixture.
This sensor can half fail and send a correct signal to the gauge and a bad one to the engine...this has little to do with outside temp, but warmer outside temps tend to make the engine run warmer than wintertime.
The temp gauge is an "idiot gauge". so you won't see these normal swings in coolant temp...the gauge (thanks to the instrument cluster processor) reads "normal" ("90C" hashmark) from 81C to 100C...dead steady needle.