By inspiring from this thread, i installed Denso Iridium IK20 & IK16 in my corolla 2009. they astonished me with the picup, and after wards with smooth driving with less fluctuation in rpm. initially i didnt feel any difference in milage, but after 3 mnth use the milage in city is 13.9km/l and on highway(khi to hyd) is 19.2km/l. i measured 4 times and result is same. Thanks to JZ for his guidence and cooperation.
