TDI AHU Problmes

[catlin_cava]

Posting this for a Friend.

after my cars warmed up if i am doing say 80 km's and let off the pedal and go to accelerate again my car will smoke and die to 1000 rpms and stay there for about a minute then will clear up, and when i start it it dont matter if its cold or warmed up it will rought idle at 1000 rpm weather i give it fuel or not and ALOT of white smoke then after about 2 minutes it will idle smoothly and work perfect, 1998 jetta tdi 1.9

[the caveman]

Get in with a scanner preferably vag-com, and check the timing when it's running bad. It may be going into a fail safe timing mode- the  timing will be  255 instead of 50-70 or so. There is a way for there to be a bad connection going to the pump and not cause a check light.