I have a 2003 1.9tdi Octavia, last winter I had the same problem as now and I changed the MAF senor. Thinking the cheap one I bought was faulty I bought a higher calibre one but this time the problem still exists. It usually happens when I accelerate, the car suddenly looses power but maintains speed, I cannot accelerate. If I stop and switch the ignition off it is fine until I accelerate again, from what I can see its usually about 3000 rpm. If I am on a level road I can still speed up but its like a non-turbo diesel.

Can anyone help??

Colin

Sticky turbo vane syndrome at a guess. Search "mr muscle". Theres a guide on here somewhere.

Odd if this only occurs in the winter (ie. when cold), so that would make me think that maybe the Coolant Temperature Sensor (CTS) was at fault rather than MAF or sticky vanes in the turbo.

Generally sticky vanes in the turbo show themselves when accelerating hard up a long uphill.

EIther way you are finding the car is dropping into limp-home mode, and the power cycling of the ignition clears the limp and allows normal power to be delivered. The fault code will still be logged (and retained) in the ECU, so getting your fault codes read. Look out for over/under boost faults and codes relating to the CTS

Thanks guys, I will look into that and let you know.