lupo sawing idle

Evening.

My Lupo is misfiring when it's hot (after about 20km on the highway followed by traffic). In my opinion, the problem is exacerbated by using accessories like lights and the brake pedal. Even without using them, the misfiring still occurs, but it's less pronounced.
I seem to recall reading something in the HST (likely referring to a specific publication or forum) about faulty hoses related to the power brake booster... Unfortunately, I couldn't find anything when I searched. Maybe someone else has some information for me.

throttle body cleaned and calibrated (learning values cannot be erased), no fault codes stored.

Sure, here's the translation:

"Thank you."

Okay: Fiat Lupo, 1.0L engine, manufactured in 1999, all-wheel drive.

Okay, I'm ready. Please provide the text you want me to translate from German to English.
I've managed to find the hst post again (I'd like to post it, but unfortunately I don't have a scanner).

What I'd actually like to know is:

The vacuum hose to the BKV (likely a component name) is becoming porous or leaky in some areas, and the manufacturer (Hst) suggests replacing the damaged sections with shorter rubber hoses.

My question: Is there already an "improved" vacuum hose available that doesn't need to be replaced?

Hi,

Thank you for the feedback. Unfortunately, I don't know if there's a better hose available.

Best regards, Rainer.