it's wise to have a benz tester on it to reset the self adaptation parameters.

Some guys disconnect the battery and start the car ten times.

I always like to replace the big rubber O-ring that cinches around the mass airflow sensor to give it a nice tight seal near the holding clips.

Have seen techs get burned by replacing the maf sensor when the weak O-ring was the original problem in the first place.

Just like any o-ring, they can get sorta squared on the edges and not make a good seal any longer.
That's why I get one every time I replace a sensor so there is no chance of it sucking air at that seal area.
The o-ring cost only about $2.oo.
Part # 028-997-97-48.
Take this part# with you because it's not in the main parts info, they have to look it up in the micro-fische.