Hello All..
I ONLY come here when I'm in a real fix.
For the last 6 months i have been living with 3 issues.
Problem 1. Juddering & noisy engine at slow cruise/traffic lights and in reverse.. Fix: Replace Injector # 2 Solved.

Problem 2. Loud blow-off noise coming from the turbo like a dump valve, with poor performance. Fix: 80% of my vacuum pipes were perished. Replaced them all. Noise gone and performance back.

Problem 3 Unsolved: Throttle delay, hesitation, lag. Example: driving from the traffic lights I press the accelerator normally and I get hardly any power at all. To get the engine to work as it should, I have to floor the pedal then all of a sudden full power surge. Another example..When cruising and I need power, again no response unless I floor it, then whoosh of power.
Another symptom of this is when the engine does kick in, I get a cloud of blue/black smoke.
Just did a full service.

Hope anyone can help..
Jon

I've experienced your 3rd issue with a 530d BMW. Bloody terrifying when you pull out of a junction and suddenly there is no power, wait, wait, wait, wheelspin/rocket off the line and angry people behind you.

It was the MAF. Didn't record any faults either. eBay part for about £15 (at the time), lasted about a week then failed, bought another and it was good for the rest of my ownership.

You can unplug it and see if there is any difference in the way the car drives, if it's the same or slightly better then you may well have your culprit. When it's unplugged (on the BMW at least) it throws the MIL on but runs on a default setting that it knows will work.

Hope this is helpful.
Richard

could be a boost pipe from turbo
it could be collapsing in on its self

Boost control valve, or map sensor failing will also contribute to no3,