Quote:
Originally Posted by andrewwynn
Twice in recent months people have reported similar and the vacuum system that controls the boost was at fault
|
+1 on this. While I've need seen this exact fault on an BMW M57, I have seen it on other brand diesels - the vacuum modulator that controls the VGT actuator becomes intermittent.
It's easy to test with a vacuum pump...
Also, VGT turbos are know to coke up and cause these symptoms, when the vanes become foulded and cannot move freely.
The above vacuum test sort of check this too, as you can see the actuator arm on the turbo more (or not).