on idle mine was reving up to the norm then revs down to 500rpm then goes back up too 1000rpm then back down to 500 etc etc never did this b4 but with the lambda unplugged it idles perfect but still plays up on driving ....

so to break down what sensors there are:-
water sensor
iscv sensor
lambda sensor
map sensor
charge air temp sensor
maf sensor (small turbo)
tp sensor
phase(big turbo)
cp sensor
knock sensor

any more???

i think mine must be the map sensor or the lambda