AOA guys,
I know its an old post, but i would like to ask you guys somethings.
First i would start by saying, I really like and appreciate the knowledge you guys posses about all these things. It's really helpful 
So I have a 1.3L Vitz (2SZ-FE) and it has been going great Alhamdulilha. There has not been any kncoking or any vibrations or anything at all. Everything has been working perfectly; however, the car started consuming a lot of Petrol. I have had periodic maintenance but the problem I encountered is that my mechanic would always take out the Iridium Denso Plugs and clean them with that that wire hard rotator. Although i told him it shouldn't be done because its iridium but he was like its Pakistan, it happens. I am using Toyota Genuine Oil Filter with Moly Green Black 5W-30 Engine oil along with Genuine Air Filter. Also the Genuine Toyota CVT Oil was changed at 37,000Kms and now car is at 61,000Km so that is still good. Also, throttle body cleaning and oxygen sensor cleaning has been done periodically.
My question is, do you guys think it can be my spark plugs that are causing fuel consumption issue? Also, the acceleration response has been less. Because i have read at alot of places that rotator type hard wire thingy cleaning can totally destroy the platinum or iridium spark plugs. Kindly share your thoughts, it will help me alot! 