I had a slight surging problem when engine was cold, and idle seemed slightly rough at times. Very intermittent. I checked the wires going to the MAF's, and found trouble. Granted, my car is a 95 with known insulation problems. I don't know what year your vehicle is, but you may have the same problem. I'm attaching a thread for you to look at. Please note that I mistakenly refer to the MAF as the Throttle Actuator initially. Later in the thread, I do get into the Throttle Actuators as well. Rewiring these components cured my problems. Lots of luck!
http://www.mbnz.org/forums/forums/thread-view.asp?tid=1202133&start=1&fid=13