Bad news, no change. :(

Sorry, sounds like a new ECU - or reprogramming. The only good news is that there are plenty for sale on ebay at prices from about £30 UK. Best of luck

I'm sorry to bump an old topic, but I've got new information to this. First of all: I didn't buy a new ECU. The ones with AC-support seem to cost like 100-200 euros on eBay, and I really can't afford that if it doesn't change anything.
The car was also unused in winter.

I got a message in Finnish VAG forum. There was one Fabia which had the same problems at similar mileage. They had changed the ECU, which didn't solve the problem.

Just in case, here's a summary of the problem:
- When releasing the throttle pedal, fuel is still injected to the engine (screen shows about 1l/100km).
- RPM starts dropping with "nudgy" motion.
- When the RPM goes low enough, the car starts shaking.
- Pressing the throttle even a little bit causes the engine braking to function normally to a point depending on the throttle position.
- Pressing the brake pedal doesn't affect the problem.
- Pressing the clutch drops the RPM to idle normally.

I don't think this has something to do with the cruise control. Personally I think the ECU somehow gets wrong information about the speed or the RPM. I guess the RPM/speed is within the threshold the ECU is expecting, because it doesn't throw an error code.

If anyone has any new ideas to this, I'd appreciate it

A faulty fuel shutoff solenoid matches your symptoms. With you foot off the throttle, the fuel shutoff solenoid should stop fueling. With light throttle pressure, it is the fuel quantity adjuster that is controlling fueling. Put a meter on the solenoid connection and see if the ECU is trying to control it.

Can you tell me where it is located? I wonder if the solenoid is faulty, how can the car engine shut down if it sticks open?
Thanks
 

Edited 17 July, 201312 yr by tmn

Can you tell me where it is located? I wonder if the solenoid is faulty, how can the car start at all?

Thanks

It is part of the fuel pump but can be replaced separately. If it is faulty, it is sticking open. In gear, with no throttle demand, it should close cutting off the fuel.

This problem has apparently been solved, can't test it since I don't have the car anymore.

I found another case of this, which was also in Finland. He had found out that this problem was caused by spare rear wheel bearings, which we're non-genuine VW spare parts. We both had these bearings sold by the same Finnish spare part company changed to our rear wheels. They apparently had wrong sized ABS rings fitted in them, which somehow caused these problems. My guess is that the wrong-sized rings somehow confused the MSR system.

The only difference between my and his car was that his ABS light turned on and gave an alarm. Mine didn't.

I wanted to post this in case anyone is interested in how this turned out. It was a really strange problem I spent a lot of time trying to solve. I also wanted to thank you all who tried to solve this with me.