986 S problem at idle, engine won't rev and shakes, battery disconnected

[Eric G]

Will be interested in seeing if this helps. I know Porsche has a "safe drive mode" where the engine will drop cylinders when the CPU detects an engine problem and gives you just enough engine to return home. The symptoms you are describing are identical to the conditions my 928 S4 would go through. No codes were thrown, but if I remember correctly it ended up being a coil related issue. On the 928 you would go from 8 cylinders to 6... I have not found if the Boxster has the same function going from 6 cylinders to 4?