Here is capture taken from a year 2000 1.8 16v Petrol Nissan Primera CMP vs CPK. The car exhibited an erratic idle, a twitching rev counter & a rough cruising fault. It had logged a P0300 random cylinder misfire code also.

The animated capture below clearly displays a problem with the relationship between cam & crank positions relative to each other.

The slack timing chain is causing a random shift in cam to crank timing. This was confirmed by removing the cam cover to view the tensioner protrusion of approximately 17mm.