Hard cold start

[Gogi]

Hello.
I have a 1991 560SEC lately out of the blue, I crank it when cold, it starts for split second then quits. Almost like its a spark issue, but then I go to restart it using the accelerator pedal and I'm able to keep it running and it's fine there after.
I've cycled the key several times to no avail. That was done to eliminate the fuel accumilator. I have not pulled the cold start injector partially out to see if it spraying only because the engine is fine if at cold start I manipulate the accelerator pedal slightly. The engine readily goes into cold idle after this.

Gogs.