[W126 Coupe] Stalling issue

[rltimmerma at cox.net]

I need some help with a stalling problem.  My 1990 560 SEC has taken to dying on rapid acceleration.

If I try to accelerate sharply from idle the engine quits.  It always starts right back with no problem and idles perfectly.  If I accelerate gently it also has no problem including WOT acceleration from moderate speeds.  I found while checking this morning that the problem doesn't happen until the engine warms up. (accelerates as it should when engine temp is cold.)

I checked the fuel pump pressure by disconnecting the supply line to the fuel distributor, installed a 0-100 psi gage and jumped fuel pump relay terminals 7 and 8.  fuel pressure is over 100psi (it pegged the gage)  I don't have the metric fittings to check the lower chamber pressure or test while the engine is running.

Am I correct in thinking this is a fuel supply problem?  Is there some electronic enrichment on rapid acceleration?

Any help is much appreciated.

Ray Timmerman