Hello, im at a loose end, i've tried asking this on another forum but i got zero replies so hopefully this will be more helpful. Firstly my car,

Ford Focus 2005
Titanium
2.0l
Diesel
140K miles

The problem is that in the cold weather (4C or less) my car starts ok but then stalls. It keeps stalling unless i hold my foot on the accelerator, once the car is warmed up it runs like a dream. When it is cold and i hold the accelerator down at about 3000rpm the rev counter randomly drops 1000rpm then recovers. If i drive off when the car is cold i randomly experience power loss in the peddle and the speedo drops to zero, but again after a split second it recovers and is fine once it has warmed up.

So far i have been to 3 garages,

The first, an independent garage, found no error codes on the ECU, the injectors were fine. They did find some air bubbles going into the injector pump from the fuel filter, so they bypassed the fuel filter, the bubbles disappeared but the car still stalled. Eventually they gave up.

The second garage, an official ford garage, at first thought i had put petrol in the car, but then realised i hadn't, which filled me with confidence in their ability. They said that when the car is cold the fuel injector pump looses pressure, so i need a new injector pump at £1000. Not keen on spending £1000 I looked elswhere.

The third garage just took a brief look, a diesel expert, said it was the wrong make of pump, siemens, and they don't have the equipment to service it properly and according to them virtually noone else does either and will cost more than a new pump to service anyway.

So im left with suggestions from friends and things i've found on the internet, they are,

Idle Air Control Valve (This seems to be the cause of 90% of stalling issues i read about on the web but the Diesel guy said he had never heard of this, is it a petrol thing??)
Automatic choke
Dodgy Battery
ECU problem

I will be testing the battery later myself to see what happens when the car stalls and looses revs.

I would really appreciate any suggestions, to be honest if i hit a brick wall im just going to live with the problem, there's no guarantee it is the injector pump and i'm not willing or able to gamble £1000 to find out.