Hi guys.... in need of some urgent knowledge please.

.....Basically had swirl flap problem... all fitted and fixed was running fine then two weeks later ( thinks its more of a coincedence) when the engine is
cold there is a metalic rattle or a really exagerated diesel knock when accelerating between 2k and 3k.... all other rev range there is just a general constant tapping sound.
if i coast and just tap accelerator so little the car doesnt speed up it makes the engine tapping louder...
There is black smoke coming out exhaust (more than normal)
also occasionally if i tap accelerator and let off it will rev right up to the redline and straight back down again (normally would only rev to 3k and come back down when pressed same amount of time...)

Also keeps being restricted to 2000rpm, flick ignition off and on and all is good again and back to normal power...
no fault codes recorded...
Alternator diode has gone causing to charge at 17.2v.... so thats in the line to be fixed but doubt that is causing all this....

im off on holiday on Monday so really really need to get to bottom of this asap. Cheers

If anyone is local to northamptonshire and wants to come and have a look for me and diagnose the problem ill sort you out , cheers