After many weeks of tinkering, and using a mercedes trouble shooting check list, someone emailed me, I put together a basic pressure gauge and 1/4 inch T piece from Home depot, I purchased some fuel hose and was able to push over the outlet and inlet of the fuel distributor and WUR. The system pressure was below 1Bar. After further reading, I took out the fuel distributor regulator to find the Green O ring totally compressed and the forward O ring hardended and broken in two. A new fuel distributor pressure regulator valve was purchased online for $51 and plenty of adjustment shims. To my great joy, after several adjustments with shims, The system pressure is back up to 5 to 5.6 bar spec.. Now come's the downer.. The replacement overhauled WUR does not seem to be modulating from cold 1.2 bar thru 3.4 bar as the engine warms up... I am back to square 1 with a rough running engine and no clue what to check next..... Any ideas?

PS, I fitted 8 new plugs, an ignition cap and brand new bosch wires..