Had a relative pop over today in his 2003 330D saloon, and in conversation I asked how it was running. He explained that he's got an issue where there's a severe lack of power under 2000 RPM, and quite a lot of smoke comes out of the exhaust at the same time. Once above 2k RPM everything is fine.
To my untrained ear (only having ever owned petrol powered cars) it sounds like a coked EGR valve. Any thoughts on this?
Unfortunately, it turns that out said relative is very green on car mechanicals, and getting meaningful info from him was hard going. When asked if it's single or twin turboed he reckoned it's the twin, but I'm sure it's not, and when I asked what the rated BHP is, as that'll give a clue as to the exact model, he reckoned it was 300 something (yea, ok). He went on to explain that he gave the car to BMW to diagnose the fault, they couldn't find any fault codes so they started guessing as to the cause and replaced what he called the mass air sensor (MAF I presume he means), but that made no difference, so BMW put the old one back on and didn't charge him for the work. They then reckoned it could be "something that costs £2000 to replace" (my relative's words), which I'm guessing could be the swirl valves...? BMW also reckoned the engine is quite coked up (having done 84k miles), but my relative thinks they're lying because "engines only coke up at 200k" (yea, ok).
So, any ideas, despite the lack of firm info? Do these engines have EGR valves and do they cause lack of power and heavy smoking below 2k RPM? Thanks.