Mates focus 225 idles slightly rough not always from cold but it misses/pops on the same revs.

So when you put even slight revs on and let rev 2k it misses, then when you let off the pedal it goes pop pop pop. All at the same revs.

I thought vacuum leak perhaps? Could timing be off slightly?

Also, when you start the car from hot or cold it revs to 2k then drops to its normal idle speed.

On another issue the PAS pump whines, the liquid is black coloured - is the pump fooked or will a fluid change sort it?

Thanks