Nissan Forum - Nissan Enthusiast Forums - 2003 Almera Tino 2.2 dci turbo problem

My 2003 Almera Tino 2.2 dci appears to have an intermitent turbo problem. Everything appears fine but sometimes it suddenly has reduced power as if the turbo is not working. Switching off the ignition momentarily clears the problem which to me suggests an electronic sensor. I had a very similar problem with a Porsche 944 Turbo that the Porsche dealer insisted was a mechanical problem with the turbo but in fact turned out to be an intermittent connection to a sensor they had changed!!!! The Nissan dealer here are suggesting it's a fuel injection pump problem that will cost EUR 3000 to fix. The first time it happened was about ten days ago. It was fine for a week and then happened several times over a couple of days which caused me to take the car to Nissan. Of course when I took them the car it was working fine again.
Has anybody else experienced this kind of problem?