sorted the coil packs a few days ago on my octy vrs and when I started it I noticed that the revs dropped below 1000rpm to the point where it almost stalls and then come back up, it does this when I start it and when I rev it also.. whats the problem while doing the coil packs I noticed split breather pipe could it be the air leak causing this..?

yes is a leak,if is bigger the engine will stall at every cold start