Ok guys here is my problem......
My EML is on....Quick rundown...
In the last week the car has had,new
Downpipe
EGR valve
Full service
Got new downpipe fitted,all good til next day EML comes on,phones AA,plugs it in and (cant remember code) basically the 'voltage' reading between the 2 exhaust sensors are not 'within tolerance'
Back to garage,gets another new downpipe fitted.......and whilst its there it gets full service.....all good......til.....
2 hours later,drives it and it starts to mis-fire slightly,then heavily.... gets it home and it goes back to the garage(no EML at this point),it gets plugged in again which shows 'mis-fire 1&2 and EGR valve fault....
So it gets a new EGR valve,all good again...
Driving great,much better response from pedal and generally feeling brill........
Last night....feels a tiny bit sluggish again and 10 mins later EML

Its not in 'limp' but the bloody light is on,phoned my mate and he reckons it could be one of the Lambda sensors,but im not sure...
I know what it is though..........getting annoying!!!
Anybody had the same or came across this?
Any help would be great,my mate who owns the garage is good,but no GM specialist so i need to try figure it.
Im hoping to get through to see hotel21 next week for software updates,so want to try solve it before i go........
Thanks in advance...