93' 190E stumbling

[rrollo]

I purchased this 1993 2.3L car with a fuel starvation problem. 123K miles. The tank has been removed and cleaned, two new fuel pumps (one bad the other was getting more noisy.) Found a bit of fine dust in the bottom of the fuel tank - like body filler dust. Fuel filter replaced twice. The car always starts well but quickly has a stumbling at first take off 1000-1500 RPM or hard low RPM acceleration. A quick rev in neutral also acts like a slight miss at first throttle movement. Ignition has new plugs, rotor, and distributor cap. Found a couple of small vacuum leaks so now the idle is steady except for the more occasional miss at idle. The performance at 2000 - 4500 RPM is very good. Drives pretty good overall except for initial throttle movement (stumble). Gets reasonable mileage. I’m on my second tank with Techtron fuel cleaner. I cracked open each injector fuel line to isolate a single injector but each opened line caused the same effect. Could the injectors (one or more) be spraying poorly at low RPM causing the low RPM stumble? I was told it might take another tank or so of fuel to run the system clean of all contamination in the injectors. I only have a couple more weeks to get my smog inspection so I would like to clear this up soon. Any ideas for this vintage CIS Mercedes? Thanks