Can anyone suggest a meaning for these symptoms

[Dirigent]

1996 E230 automatic - went into around 3000-4000 rpm and then would not slow down, I had to put the selector in neutral. The engine carried on at 3000-4000 oscillating. Eventually, whilst stationary, and of its own accord, the engine calmed down to idling speed, and I was able to proceed home with no further mishap.

In recent weeks, after a reasonably fast (70mph) run, on slowing down the engine has subsequently failed to pick up when the accelerator is depressed. This seems to be, usually, curable, by a short time at high rpm. Now, however, with the oscillating high rpm symptom, the situation appears to be worsening.

If anyone can think of what this might be, I'd be very grateful for a hint. Though please explain simply!

 

[camerontyler]

As a non mechanical person the only advice I can give is -

DONT USE THE BL**Y THING!

Get it to a mercedes Indie asap, preferably on the back on a lorry so you don't die on the way.
I wish I was joking but if it get stuck at speed and won't slow down you may end up killing yourself and someone else (or a whole family) in the process.

I googled merc indie north wiltshire and this is the first that came up, give them a phone and get a bus in the meantime.

PC Autocare - BMW Mercedes Air Conditioning Service Inspection Swindon

 

[grober]

Problem with your electronic throttle sender unit /cable/pedal or the throttle actuator jamming/malfunctioning. The internal wiring insulation on the throttle actuator is known to degrade with time causing weird symptoms- have a careful look at the state of the wiring. Getting the fault codes read may help pinpoint the problem. The 111 engine is a pretty reliable unit but it is 14 years old!

 

[trapperjohn]

If you have cruise control that can add to the mix of trouble aswell. Do you have cruise control?

 

[Dirigent]

Yes, there is cruise control. Which seems towork fine whenever I have used it.

Last evening was the first time there has been the symptom first described, and I plan to get to one of the NWilts. specialists as soon as I can (thank you for the link CameronTyler).

Grober, thank you for the ideas - which will give me something at least to discuss with a specialist - though I suspect they will blind me with science rapidly thereafter.