Lonewulf

So I just bought my first 240sx about 4 days ago. It?s a 1995 S14 coupe. When I bought it. It had a tick from the timing chain which is getting a new timing kit soon. It ran and drove but it was sluggish and sputtered and also had a leaking i injector. I just went ahead and replaced all of the injectors along with a new fuel filter and that solved my sputtering problem. It is kinda low on oil and the oil in there is dirty, I plan on doing a oil change later today. Anyways yesterday when I went to start it, it started right up no problem and the sputter went away but I noticed as I revved it, it had some grey or white smoke coming out the exhaust and a decent amount of it. As I let off and let it idle and slowed down a ton and was just a tiny bit of smoke. I?m thinking it?s not the head gasket cause if it were it would be pouring out smoke even at idle right? Let me know if you have any advice or if you have had the same problem and how you solved it! Thanks!