Seat Altea tdi 2.0

[Jeank]

First of all,thank you for adding me.
Im the proud owner of a 2009 Seat Altea 2.0 tdi...proud to be part of the VW family,but also a rude introduction to VWG ownership..
I need help before i give up and sell my baby..
History:
Bought this car on a bank repo auction,when i collected it,it was very hard to start,but adding some diesel,we eventually got it going,filled her up,added some Wyns diesel injector cleaner and drove it home +- 300km..first of all the car was lazy on pull away and was constantly stalling on pull away,as the roads opened up,so did the performance improve,but still had to 'spool' it up on pullaway and stumbled on idke a coupke of times stalling the engine.
The next morning back at home,i did a oil change,oil filter,new air filter and diesel filter...still,starting it from cold is difficult,but after a couple of tries it eventually starts and idles fine at +-850 to 900rpm..
Took it on the toad today snd i must say it pulls great,especially from 2000 rpm when the turbo spools up,had a great trip for 25 km and comming to my first intersection it stalled on me..i battled to get it started,but after sbout 6 tries,it eventually started up,but not picking up rpm at all,it sat at 1000rpm for about 2 min with my foot planted on the accelerator..it eventually cleared up and i could drive off..power came back slowly and after about 2km,it was back to normal..pulled away at another intersection,went trough the gears up to 5th and then problems..it refused to past 100km/h with my foot planted,even in 6th it lost speed,down to 4th,still the same,as i neared my town,it felt sliggtly better,but going ildown gears and then up,the car felt dead,no power,no turbo surge as usual,pulled into my driveway and switched the car off,5 min later started up right away,idled fine,no problems.
Please i need help,i cant trust the car as it is now,im to scared its going to leave me stranded.where do i start looking? There are no illuminated warning lights on the dash,no excessive smoke,nothing...

[TD HIGH]

Best to have it scanned for faults, where abouts do you stay?

[panic-mechanic]

Yup impossible to even start guessing without seeing what it complains about. Also diesels that stood for a long time you should drain the fuel and put fresh fuel in. There is a bacteria that grows in diesel and when it sucks that into the filters it will clog up the filters.