Audi 80 TDI 1.9
 

Curious problem on 1994 Audi 1.9 Tdi:
(sorry for my english...)

driving at 150 Km/h, engine loss power and goes down to 120 Km/h... If I
rise my foot and press gas again, power comes back and speed goes to
150-160... but some minutes later the problem appears again... I repeat
rising my foot and pressing again and engine recovers power for some
minutes...
Driving at 130/140 Km/h the problem does not appear...
What is the problem?
Filters, pump, everything has been checked but problem is still there...

thanks for help.

Tj / Spain