I have been having some issues with the A4 recently. My local independent replaced a vacuum hose and this had the car back to normal, but this morning on starting the car I had white smoke and eventually the car would stall.
After doing some diagnosis I pulled the vacuum hose out of the EGR and all was fine. Took the car on a test drive and it was perfect.
With this finding I thought I would take out the EGR and Inlet Manifold and give it a good clean to see if I could solve the issue.
One thing to worth noting if your thinking of doing it yourself, best to do this outside as its a dirty job. I did it inside today because of the rain.
Took about 4 hours with 2 1/2 of that crud removal.
I used various screw drivers and bendy things to scrape crud out, contact cleaner and wet and dry.
Carbon from EGR
Carbon from Intake Manifold
And finally me turning into Papa Lazarou
Car is driving fine afterwards, haven't driven the car with the vacuum hose plugged in, but it drives fine without and now idles find with the hose connected back up. Will properly test it tomorrow.