I have oil consumption issue in my car where there is white/blue i cant really tell when the car is cold but it stops after moving, i have kept an eye on the oil level and it dropped after driving 1500km on 20w50 oil SL, the mechanic did a test to know if its valve stem or piston rings he pressed accelerate too high that dark smoke came out but not white or blue he told me that piston rings are fine, i took out spark plugs to check on them and 3 out of 4 look like the pictures i have attached, i drive 1997 Mitsubishi lancer 1300cc