Never trust "experts!" There aren't too many of us left actually..
if it stalls at the lights it's too lean. If it is idling too high,it will be running lean because they have screwed the air by pass screw out too far. Screw it back in again .
If it is still stalling the nerxt step is a cheater move. The link to thev pjump itself can be shortned so the pump is slightly opened . This means that the throttle is closed but the pump is beginning to pump fuel. It will still idle ok but shouldn't stall as easily.
it's hard to diagnose a system after someone else in another country has messed with it .
As i mentiioned before,Pelican parts has a really data base of anything you would need to know. It does deal with the Mfi as bolted to Poerkers but it's exactly the same syastem as fitted to MFi mercedes engines. Same principles of repair apply.
Pelican Technical Article: Mechanical Fuel Injection Troubleshooting and Adjustment - 911 (1969-73) -

if your expert can find a pump for 5 grand I will take a few. Last time I got a price for the 8 plunger pump it was $48,000 .