91 560SEC w/ surges when starting

[BCA Design]

Just had a major service and timing chain replaced at 167k.
Prior to the service, car required about 6-8 seconds of cranking to fire up, produced a couple of shudders, then settled down.
Now, upon starting the engine "flares up" to 2500-2800 rpm then comes back down and dies. On second start 5 seconds or so of cranking is required, then shudders for a few seconds and then settles down.
This routine is pretty consistent on both cold morning starts and after vehicle has been parked 30 minutes or more.
Service Tech at dealer said the solution was to replace the fuel injectors. Since the car runs impeccably at all speeds and stop/start driving, etc... I wonder if there is anything I should look at first, before replacing major parts ? Any threads on this symptom ?

As always, thank you for your assistance, folks !

[Benzmac]

The injection nozzles could be the problem, but may not fix a thing. I would probably check everything else first and do them last.

They may fix the problem...

Mine does the same shuddering. Said it is a leaking fuel injector but can't tell me which one, plugs should tell. They are only $27 a piece, for a benz, that's a bargain.