CLK 500 (W209) "ESP defective, visit workshop!" And engine light

[Fivehunnit]

So, today while accelerating, suddenly the car started to lurch and sort of try and stall, I got a warning like (ESP defective, visit workshop!) and the car cut out when I came to a stop.
It then started normally but the engine light is in, it runs with a slight hesitation upon accelleration now, but the malfunction warning hasn't happened again, any ideas?

 

[Fivehunnit]

Update

This morning I came to rest at a junction and suddenly it accellerated something fierce, had I not been on the ball, I would've ended up putting a big mercedes imprint in someone's door.
The engine check light is still on, still split second hesitation when the throttle is pressed, I can get it to the floor and back with no increase in revs, but under normal driving it's not totally unmanageable (for now).
Is it likely to be the throttle position sensor? And if so, which one? Does it have one on the pedal and one/several on the throttle body? Is there any way of testing such as if there is lag in the pedal but the throttle responds ok when operated by hand at the body? (Can't find that as yet).

 

[DSM10000]

The most effective way to solve the problem is to have a Star diagnostic carried out, anything else could lead to expensive guesswork.

Hope it is easily fixed, report back what you find

 

[Fivehunnit]

The most effective way to solve the problem is to have a Star diagnostic carried out, anything else could lead to expensive guesswork.

Hope it is easily fixed, report back what you find

Thanks, will do.
If it turns out to be the pedal/sensor, are they all the same for the W209, or are they all different depending on engine size etc?