While we are talking about LOS on P8, here is some info for you:
By far the most common cause for running problems on a P8 managed vehicle is the special ‘limp home’ mode enabling. This will prevent the vehicle revving past 4000rpm both at idle and under load once the engine is hot. When this safety feature is activated it will not rev past 4000rpm and you will experience what feels like a misfire that you cannot rev through.
The limp home feature is designed to protect the engine from damage, whilst still allowing the vehicle to be driven home, avoiding the unpleasant experience of being left at the side of the road. The vehicle will only go into limp home mode when it detects an error condition, this error can be caused by a number of things; such as sensors having failed, sensors plugged in incorrectly, poor earths to the ECU, lambda sensor being unplugged (or fuse failure) etc.
A large number of chip retailers use a facility to turn this limp home feature off within the chip, including virtually all chip suppliers using Pectel products. This is normally done either for competition vehicles or to avoid dealing with running problems encountered after the sale of a chip has increased engine power and highlighted other shortcomings, thus limiting the after sales support required. A sad but true fact.
However, as I’m sure you can appreciate, running without this feature offers no protection to your engine in the event of a sensor failure or other potentially damaging condition. We have always prided ourselves on ensuring reliability and safety for your engine and as such, use this feature within our chips, in fact, on our latest software calibrations we have enhanced the system even further. If you are experiencing running problems of this nature then we recommend all sensors are checked for condition and correct operation, starting with the lambda sensor and associated circuits as this is the most common cause of the system being enabled.