yeah its probably the rings.
my camry did the same thing.

sits hi and low on idle. poors out smoke ramdomly while on idle. chewed oil like no tomorrow.

got the head gasket fixed..

and still munched oil. and idled up and down and still blew smoke.. then 2 weeks later it was a camry but sounded like a rexxy. changed the leads and spark plugs thinking it was that since the head gasket was fixed. but then realised it was piston rings. one cylinder seized up then sold it for $400.

running on 3cyl.. then GG for the motor. then i got a civic

LOL