Hi,
I am driving a `99 Boxster 2.5.
This car has lately developed a misfire only when the car idles at working temperature.When the car is cold there is no misfire and when driving the car the engine runs smoothly. The engine management light remains on .
The fault codes indicate that the three cylinders on bank 1 all misfire I have replaced the lambda sensor on bank 1 but the problem persists
Any suggestions what causes the rough idling and how to address the problem?