Mine appears to run with a lamba as it runs like crap if you dissconnect it !!

I realised i had the probelm when I initially went for an MOT it was running 0.37% at idle. take it back a few days later and it now runs 9.5% (noting electrical touched !) . The rolling road operator says that when it starts too boost (3000rpm) the lamba sensor switches over and fueling is fine on boost, just off boost it seems far to rich !!.

Here was what Stu from MD said ...

''lambda sensors can be faulty and still work, its the swicthing time thats affected, but in many cases, the internal heater fails and then the sensor is innacurate until the exhaust gas gets hot... IE, higher RPM.
The sensor needs a nominal tip temperature of 750degrees C, its crucial it stays up there or it will foul amongst other things, thats why they have a heater ''

The software number on the pectel board is issue no 1 (18/05/99) ....

Any suggestions what i should try first ?? i suppose i should buy a volt meter first !

Map , Lamba ??