NA6 stock ECU tuning - definite torque flat-spots etc.

[ampz]

Just adding to Juffa's and STM's post.
Overtightening of the timing belt is possible, it may also be a tooth out, making your engine work a little differently to what it was designed for.
If your injectors are in need of cleaning, they may be spraying irregular fuel patterns (running a little rich as the fuel dribbles out rather than spraying out).
I noticed this when i changed injectors, which i had cleaned prior to installing them.
My idle was a lot smoother and so was light throttle driving.
Maybe one thing to check.

[93_Clubman]

is it normal for a mechanic to overtighten a timing belt to allow for stretching?
when i got my car back from having the waterpump, plugs, air filter etc replaced, he told me there's a "bit of a whining noise, because i found the timing belt was loose after i replaced the waterpump..." (der) the noise almost sounds like it's supercharged haha. i freaking wish!

short nose crank problem also starts with a bit of a whining noise, but you'd hope that when the waterpump was being done that would have been noticed...

[bensale]

Its also possible the whining noise is coming from the accesory belts. Spray some water or maybe wd40 at them and see if it goes away. I fitted a certain brand of belt (can't remeber) and it made one hell of a whine (like a s/c) when not tensioned perfectly.