This is called throwing parts at a problem. I have never understood the reluctance to admit that you don't understand the complex nature of a automotive system.

So off we go replacing fuel pumps, fuel accumulators, etc. etc. In the end you spend more money than the cost of a diagnostic visit to your friendly local MB specialist shop.

All they would have to do is keep it overnight and start it up with their meters attached. They also know how to pull the codes. Then you will have the answer and can choose to have them do it or do it yourself.

I can tell you for sure that getting the M103 correctly repaired and adjusted is not something I would do myself. I watched and listened to a mechanic with 30 some years experience as he got my M103 '92 300E back on the road after it suddenly died out of state. He replaced the EHA, Idle Adjust Valve, Cold Start Valve, the coolant sensor, Oxygen Sensor etc etc. He replaced some of these after diagnosis. Some were optional, but I told him I wanted to error on the safe side. There is expertise and knowledge involved in adjusting the system.

Still running nicely 70,000 mile later.

Steve