OH NO, GRAYISH EXHAUST SMOKE!

I was doing mild accelerating last night and noticed smoke coming from exhaust in the rear view mirror. I am hoping this is not something serious. I spent the morning in the factory service manual to see what I could find and not much. I have noticed strong odor from exhaust when idling also like it is running rich. I hope not burning oil. I can't remember the differences between color of smoke i.e. blue versus white or gray and any help would be appreciated. I'm going to pull the spark plugs today and change it and the fuel filter.

I have been going through the car maintenance wise and trying to learn all about the ZR-1. Yesterday was first oil change for engine, trans and differential and replaced master cylinder. PCV valve were also replaced.

Thanks for tips in advance.