Same here, my MOT tester always struggled to get my diesel transit to pass, even though I always did the "Italian tune-up" on the way to the garage. This stuff sorted it.
Is this how VW made their diesels appear to be compliant? Given emissions are responsible for tens of thousands of deaths every year it seems short-sighted to just use it to pass a test...
Works for me too, I've not failed on emissions in 3 years of using this, but failed almost every year of the previous 4 or 5
This did the trick for me and got my car through the MOT after it failed on emissions