I previously submitted a post regarding the engine surging on my '95 E320. the computer gave codes 2 and 3, so I replaced the O2 sensor, and while this seems to have helped a little, it has not solved the problem. The check engine light has not come on again over the last three days, but there is still some surging, albeit slightly less than the dropping to 500 RPM and surging to 1500 RPM. it's not too noticable while driving, although I can feel some hesitation and surging. mostly noticable when I come to a stop, when I pull my foot off the gas, it will drop to around 500 RPM and surge up to 1000 or so. pop it in neutral and it will do this drop and surge a couple of times then settle in at around 700 RPM, but the idle is a little shakey. I thought maybe EGR valve due to the shakyness, but the surge sounds more like mass air meter or throttle body issues. Can problems with the injectors cause this issue? can the throttle body be cleaned out? or is it a replacement item?

Thanks!