Hi everyone and thanks for viewing my post.

My Mini - 2006 R56 N14 Cooper S Auto 75000kms

Issue = Surging or Hunting at light throttle and more noticeable at low speeds.

Idle is smooth, acceleration is normal. The symptoms appeared after recent repairs.

I originally had 2 issues which I had a local repairer fix recently. A death rattle and poor idle cold and poor performance cold. Diagnosis was HPFP and Chain guides and tensioner. Death rattle is now gone and poor idle and performance cold is no more. No codes are being registered.

To experience the issue I accelerate to 30 kph and gently take my foot off the throttle to maintain a constant speed. The engine begins to surge/hunt very gently as if the mixtures have gone lean. If I accelerate to 40 kph the surging disappears until the light throttle is applied again. The higher the speed the less noticeable the surge. At 120 kph I can no longer feel any surging.

As far as performance goes this Mini is great to drive but I hate the constant throttle surge.

I've been to a BMW mechanic, he scratched his head. I went to a Dyno and was advised the fuel pressures, fuel mixture curve and ignition system are within specifications.

What is causing the surge/hunting - any suggestions/direction would be appreciated.

Many thanks