This (bas esp and limp to stop) happened on both my sons SLK32 and my SL55 more than a few times. In both cases, the throttlebody was not bad, it was the connector on the harness plugging into it. Later mercedes models actually had a short (male/female) extender harness that came glued into the throttlebody (presumably to seal/immobilize the connection). You may get away with merely cleaning the connector with a good contact cleaner (part of the mercedes service procedure for the TB IIRC).

it would most often happen after some hard acceleration (on more than one ocassion, I had just passed a line of cars on a winding road then crapped out and I had to roll to a stop looking like a D-bag).

On both cars, I tried cleaning the connectors and they would eventually fail again.

On my sons SLK32, I replaced the harness from from the ECU to the TB and the problem went away.

On my SL55, I added the male/female extender harness and the problem went away. (I was actually using it as a troubleshooting step as I expected the problem to persist and I could isolate it to either the harness connector or the TB .... but the problem went away and I left the extender harness in place)


I have the part number for the extender harness somewhere ($50 IIRC) and I also have part numbers for the housing and pins for a DIY re-connectorization ($12 or so I think)

hope that helps,
Chris