Hi all. 
This is my first post and i'm sorry to say i need help.
I've done the usual and searched the internet and cant find my symptoms anywhere. (many similar but not the same).
I bought 6 months ago a fantastic condition German model 320d that had been imported to Spain in 2006.
The car has zero rust and has been very well maintained.
The car has been a dream to own till last week.
I took it to a jet wash, pulled in and switched off the ignition.
I realised that i had no change in the car and started it back up to go and get some. (car never got wet).
The car started perfectly and off i went.
20 seconds later the car juddered and lost power and continued juddering, trying to cut out. (no engine light).
I went to my local garage and they cant even look at it till 3 weeks time.
I would love to eliminate as many problems it might be and possibly solve it. 
I've recently changed all boost pipes and cleaned the maf/egr and this has made no difference.
The car starts perfectly every time and idle is perfect.
When i touch the throttle it'll rev to about 1500 rpm then cough splutter and spit smoke (runs real rough) and idle is bad (lumpy and coughing).
If i switch off the engine and start again exactly the same again, perfect idle till i touch the throttle and it fails the same again.
If anybody has any great words of wisdom or experience please let me know.
Once again the car hasnt been to the garage yet so i have no fault codes.
Thank you very much in advance for reading this post and look forward to any helpful advice

Is there any possibility that you have misfuelled the car and accidentally put in petrol instead of diesel?

Assuming Trevor isn't right about misfuelling  I have 3 thoughts 1st have you checked the MAF try unplugging it, 2nd possibility is the throttle body when they fail they give similar symptoms the fault will read something like "throttle position sensor", 3rd turbo issues sticking actuator or split pipe somewhere. I did read some years ago that there is a seal between the boost pipe and the turbo which can be dislodged which causes power loss? I would go back carefully over the work done in case something is dislodged or loose. When you cleaned the MAF what with as they can be easily damaged.

Hope this helps

Dave