Guys, I could do with your thoughts on this. Driving along A38 at just under 70 in 5th (Golf Mk5 1.9 TDi) when I felt a single pulse through the accelerator pedal and then power was lost even when I welded my foot to the floor.

Dropped to 4th and all was well again. Then later at 40 in 4th same again and dropped to 3rd to no avail. I thought I was breaking down so I put my hazards on but it turned out to be ok once I dropped to 2nd.

Something amiss though. Any thoughts? LL.B (Hons) - University of Derby
LOT (Lord of Time) - University of Gallifrey

If it feels like a petrol engine having the ignition momentarily switched off, the first thing I would suggest trying would be to replace the crankshaft position sensor.

Nick (Now Sold). 2008 Freelander 2 (Nazca Sand) SE TD4 Auto. Statutory write off & on WOVR for hail damage but still road legal.
171037Km as of 09/05/22
Superchips Bluefin Flash
Nanocom Evo II (also sold)

MAF or MAP sensors also seem a good place to look, does sound like it could be a dodgy sensor or wiring somewhere.

I've had that same thing happen on the VW engine.
Twice it was the mass airflow sensor. Replacement needed both times, don't try to clean it, it didn't work for me.
The third time was the catalyst destroying itself which eventually blew the remains out of the exhaust.

A good plug-in code reader will tell you where best to look.

Thanks guys. I Googled the MAS issue Marcus and some of the symptoms seem to correlate. I was worried it was the turbo.

Hope it holds out during the car shopping I am undertaking then if I buy something else, I can hand the car over and not have to worry about it. LL.B (Hons) - University of Derby
LOT (Lord of Time) - University of Gallifrey