Good morning all,
Since owning my Series 3 Roadster I have experienced intermittent P0133 MIL situations which some say can be quite common on these engines. `I usually just turn the MIL off . I changed the sensors upstream when it first happened at 8000 miles and now, at 20000 miles it is happening again. I took them out and left them in petrol to clean them as they were very black. It is always the right hand side upstream sensor which triggers the slow response signal. Some times the engine will run fast for a while, particularly when cold and some times it will do so even when hot. A couple of days ago I thought that I would experiment with a right angled extender and in the course of so doing drove 160 milles of mixed motorway and urban roads. The car performed faultlessly: no mil, no rev hang, smooth running and 34 mpg. Is it then obvious that the sensor is at fault or is that a red herring and I should look elsewhere ? I wouldn't have thought that the MAF sensor needed cleaning but I could be wrong and I cannot sense any leaks. Two days ago the car went for its control technique and passed with no advisories.
