First of all do the ECU reset proceedure, you will find it under miracle cure in the FAQ section. Your ECU is still trying to run with the old MAF settings. Try it , it may work, may not....
If not then try this:
The throttle butterfly is located inside the metal housing to the right of the plenum chamber mate (the item that has V6 24v stamped in red)
Just unscrew the jubilee clip that holds on the rubber hose and you will see the brass disc (the butterfly)
Clean the throttle butterfly. A lot of crud can build up around the inner edge of the throttle body preventing it from positioning correctly. It therefore constantly tries to correct itself on fly-by-wire, thus the revs fluctuate. Just don't move the butterfly with your hand!
Get someone to press down on the throttle with the ignition on if it's fly-by-wire CF2/3. (CF1 uses a throttle cable).
Clean round the edges where the throttle butterfly seats when closed. Use a good carb cleaner spray and just a tiny amount of WD40 sprayed onto the top and bottom of the bar that holds the butterfly valve in place.... Job done!
You could also try removing the plastic cover carefully that sits on the side of the throttlebody,(CF2/3) this houses the gear wheels and electric motor for the fly-by-wire sytem and again, dirt can build up on the gear cogs preventing full range of motion. Do not touch anything inside..... Simply spray a liberal amount of the electrical contact cleaner into it so that the dirt runs out and follow up with a very light spray of WD40 to lubricate... Refit the cover
Also inspect the rubber/ plastic induction hose from MAF housing to throttle body thoroughly for any cracks and splits no matter how tiny. Any air that can get in after the MAF will throw out your ECU settings and cause rough idle and running as it tries to correct itself.
Always remember with MAF's and lambda sensors "what goes in must must calculate with what goes out" or the ECU has a dickyfit