Mercedes 350 se w116 model v8 misfires sometimes idles on 6-7 cy

Hi,You need to carefully take out the injectors making sure you don`t break the rubber O rings after depressurising the system,then leave them to soak in petrol overnight,you then need to blow them out with an air blower attached to a compressor,by making a snug fit to the inlet side of the injector,a short blast should make a peeeep noise when you do this ,just a couple of short blasts if you have some carb cleaner spray you can sometimes get the little spray tube in the top of the injector to do the same thing,BE WARNED carb cleaner is very powerful solvent and not nice to you or anything else but is really good at cleaning out injectors so use a rag to catch the spray,I have done this lots of times and is cheaper than new injectors at £120.00 each if they are still no good after cleaning them you will have no choice but to replace them,the fuel distribution heads are also prone for siezeing so you need to check this but if it runs on 6 it should only be the injectors stuck due to dried petrol corrosion inside,Hope it works,let me know
Darren.