Problems with Mercedes Benz 300E Year 1987

Hello everyone, I have a Mercedes Benz 300e year 1987, automatic and I have the following problem: it costs to start, I have to give it several times starting that leaving that if 1st work the benzine pump, after several attempts 8 or more times definitely starts, but at the beginning as it was working in less cylinders and the few seconds it stabilizes and it is working even, if at the time or 2 hours later, if at the time or 2 hours. Start again, it starts without any problem, but since the last time it started if I let 4 or more hours without starting, when trying again the same situation already commented (giving several starts). In addition, what is happening to me now (2 days ago) is that the benzine bomb apparently is not working because it does not sound when I open contact and after several attempts it starts working and then again stops working and so on. This did not happen before.
When checking the spark plugs they do not get wet and the spark when trying the cables is also good. I have a manual of Mercedes Benz cars in PDF, but in this it does not come out for example which is the type of benzine pump that uses my car. I have been told that there may be dirty injectors problems or the pressure regulator that is failing and the same could happen with the benzine pump. It gives me the impression that the problem should not be much because after the car starts and as long as it does not let many hours pass it again, it works without problems, for example being minimal it works between 700 and 800 rpm even. After all this exhibition I need advice from experts who know mainly from the failures and possible repairs of this type of vehicle (it is equal to the attached photo and even color). From now on thanks to those who can contribute.