E320 CDI power loss (W211 2005 69K miles)
 

Hi
I bought this car a year ago in the UK from a franchised Merc dealer and have suffered an intermittent power loss problem, typically after driving at 80mph for an hour or two in cruise.

I only notice the problem when I need a bit more power to pass another car and then realise that there is no kickdown and the car doesnt want to pull any faster. The problem disappears when I pull over for a few minutes with the engine off.

I have driven about 30K miles in the year since I bought the car and this problem was happening every 7/8k miles but now is happening more frequently (2/3k miles) although it is completely unpredictable and always disappears after. There have never been any warning lights on the dash apart from the very first time this happened when the engine warning light came on.

The Mercedes dealership have had my car in for 5 or 6 times to deal with this and have replaced sensors in the exhaust that were apparently registering too high temperatures and, before this weekend's failure, they had just replaced the ECU under warranty. My warranty runs out this week so concerned at the problem further escalating and leaving me with a big bill.

Any thoughts from the experts out out there would be appreciated!
Thanks
Darren