Power loss at low rpm

[Bmw02er]

Since a little while the car suffers from a lack of power at rpm's below ~3k. This occurs especially when cold, but not necessarily. Then the engine starts bucking a little as if kicking out a bad hangover. After that, in the higher rpm's, there's nothing the matter.

I suspect bad ignition but I can't seem to relate that to rpm. I also have a leaky center exhaust pipe which I need to replace one of these days. Could it be there's a lack of counter-pressure from the exhaust system at low rpm?

Tia!

[BlueBMW]

Usually idle and low rpm issues seem to be caused by vacuum leaks.  Ignition problems I'd think would show up at high rpms also.  Is the mess under the intake done already?  Also, I highly recommend the COP conversion.  It works amazing!

[Bmw02er]

Yes I already took care of the snake nest a year and a half ago. As far as I know that's only relevant for the icv.

I was thinking going cop but first the car has to pass mot. If I get past that without spending I'll invest in cop.

[BlueBMW]

Would cop get you in trouble for mot?  If anything I'd think it'd improve things