Astra 1.3 Diesel low power after starting / Reply

Hi Guys , hope you can help as this is driving me nuts.
Have a 55 plate Astra 1.3 diesel estate which 50% of the time has a severe power shortage after starting from cold in the morning. I know it isnt exactly a ball of fire performance wise but it is adequate for my needs.
After starting in the morning it feels as if turbo isnt doing anything as the "surge" in acceleration just doesnt happen. The engine struggles to pull with any power at all and then after approx 1 mile it picks up and is then ok. Engine management light doesnt come on and it doesnt happen every day although it is getting more frequent ( 5 mornings last week). Problem did occur when new (Twice in 6 months). Took it to dealers last week who said there is no fault code, they kept it for 2 days and couldnt get the problem to reoccur. They changed the "air mass" whatever that is (I believe it monitors air flow from blower).
Would be grateful for any help from your massed ranks as this is getting on my nerves now as I pull out onto a busy road within 100 yards and need that acceleration, (Not that its a lot to start with lol)

What other checks did they perform, as it sounds like a vacuum related error

I dont know but I suspect they didnt do much, is there anything i can check.

Not really, it's all management controlled, but i would be looking at the vacuum pipes around the boost pressure sensor, trouble is if the boost sensor is intermittant then you havn't a hells chance is spotting it, the dealer should have been looking through the datalist (which i suspect they havn't) as there were obviously no codes and no running probs during there testing.
There are concerns with carbon buildup in the inlet manifold/egr on these engines, and also turbo failure, but, once present they tend to not improve.

ok tks, could you tell me where this sensor is, and is it a piece that I can do anything with. It is a company car so the expense doesnt bother me I just want it fixed, at the moment it just isnt safe as I cant rely on the acceleration when starting from cold. Car has done 50000 miles and been "regularly serviced by dealer".

Out of interest, in the normal way when the car performs as it should, what is acceleration like?

A bit sluggish for a second or two, then there is a surge Which i assume is the charger reaching speed,but otherwise its not bad considering its a 1300 diesel. A good car which gives 46mpg fully loaded with ladders on top ( I'm a service engineer), take all the rubbish out and throw away the ladders and its easily good for 50+ mpg, cruises happily at 80, 70 mph at just above 2000 rpm tks to 6 speed box.

Is it an Astra H? If so all of them when cold do not accelerate as hard so as not to damage a cold engine, but its not usually noticeable (well, I've never really noticed a difference in mine)

According to manual its a z13 dth and this is a definite power drop, there is no surge when accelerating, it is as if the management system is pulling it back or the blower not blowing.

Ah interesting. I often wondered what a 1.3 tdi was like in an astra as i drive a 1.4 petrol.