Air in the fuel system.
Driving along at highway speeds, the lift pump is pulling fuel from the tank fairly quickly. Any poor hoses may start to leak air into the fuel. At highway speeds, there can be a fair bit of air there, but because of the high RPM, the air is sent thru the return line as it enters.
Stop at the lights, the air tends to accumulate in high spots and may, when you floor the car, be enough to give poor performance, but not enough to cause stalling or specific missing, until it is purged from the IP. This may take minuted for this to occur.
Check for air in the return line when you come down to idle. Check all hoses for deterioration and any moistness should initiate the replacement of that hose.

This gets worse as the fuel tank level drops, and is made worse by any restriction in the fuel system prior to the lift pump.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.