Volkswagen: Cabriolet Fluctuating Idle when warm, elbow grease, techron

Question
Hi, mine is an 86 cabriolet in very nice condition. It happens only at the time when engine is first warmed up, maybe after 5-10 minutes of starting up. I have replaced the O2 sensor, all new cap/rotor/plugs/wires, and it's still there.

Answer
Start with a bottle of high quality injector cleaner like Techron.  If that does not do it, clean the throttle body.  When done, make sure it looks like new, both sides.  A good throttle body cleaner, some elbow grease and some patience should do it.

Rob