A bit more info on this.
The symptoms have developed a bit.
When cold, the car starts up and idles around 900 rpm, pressing the brake pedal causes the rpm to drop to about 700 rpm the idle becomes very lumpy with the engine shaking. Releasing the pedal it stays lumpy.
If the brake pedal is not touched the idle is fine.
The car stays stuttery when driving around 2000 rpm, and slowing down to a stop the lumpy idle takes over and it stutters to a stop. Only when really warm the symptons more or less dissapear, after 40 mins driving.
I have resistance tested the lift injector (king injector) and got 100 Ohms, so that seems fine.
I connected an air line up to the map sensor, the resistance does change but only by about 3 Ohms, 3500 to 3503 Ohms. Seems like a very narrow range.
I have a pressure gauge on the turbo, it reads steady doesn't seem to be a leak.
I remade and checked all the main body earths.
Disconnected the alternator, to see if this was dragging the engine,( it wasn't)
Cleaned and tested egr valve. Ok.
The only thing I did find, was nestling among the glow plugs seem to be 3 water temp sensors, they are not mentioned in the manual.
Why are there 3 and what do they do?
Interestlingly 2 of them read between 200 and 900 Ohms. the one in the picture read open circuit, could this be the problem.
I can't understand why the revs drop when the brake pedal is pressed, it's not an engine vacuum driven system.
So I'm still stumped, I'll replace that water sensor. Could a temp sensor cause all this trouble?
sensor by
Sovereign125a, on Flickr