Car spluttering on cold starts

[funkymonkey]

Starting about a week ago, whenever I cold start my car, for the first 2 minutes of driving the engine splutters a lil, and I hear pops out of the exhaust etc. What could be causing this? bad sparks? engine on its way out?

oh its the N/A RB20DE I'm talkin about here, not the new engine.

After the engine warms up its all good, no shenanigans. Although I've also noticed the idling is a bit unsteady at times, and occasionally while iding the car shakes likes its about to stall for a second then revs up and a lil then goes back to idling normally.

Something strange is up.