[Bellehayes]

My 2000 model Boxster S manual 190 000km has developed a rough idle - hunting - when the ac is switched on. When off, idle is rock steady at 800 r/min.
Trawling through the various forums suggesting clogged MAF or dirty throttle body doesn't seem to apply as all is well when ac is off although pick up on acceleration from standstill is a bit jerky and isn't quite as smooth as it used to be. I have also noticed occasional pinking - pre-ignition under load. Our best fuel here in Cape Town is 95 octane.
Two other issues, probably unrelated are driver's side radiator fan has stopped working (RHD) - determined that new fan motor is required, relays check out OK and fan is dead on both high and low speeds.
Finally, radio interference when I press the brake peddle even when stationary.
I recently replaced all rotors and pads from a complete Brembo kit including shims, wear sensors, etc. That's when I noticed the radio interference.
Could the issues be related?
Any suggestions will be appreciated.