Thailand Ministry of Commerce regulates that a deposit control additive being added to market gasoline must pass BMW 318i's IVD test and Chrysler 2.2L's PFI test. A fleet test on how commercial IVD detergent additive packages contribute to PFI, IVD, and CCD is done. Based on the highest market share in Thailand, twelve Toyota Corolla are selected. Three commercial IVD detergent additive packages passing the above test: Polyether amine, Polyisobutylene amine, and Polyisobutylene succinimide, each combined with synthetic carrier fluid are used to represent the different classes of IVD detergent additive. The test vehicles are assigned into 3 groups. Each group of vehicles runs on base fuel and three additized fuel, accumulated 20,000 km. (40% city driving and 60% highway driving) in each test in the program.Result indicates that base gasoline in Thailand is not affective to port fuel injector. Therefore, we are unable to differentiate PFI 's performance of each additive. However, it is found that these additives reduce 45-60% intake valve deposit from base fuel and somehow increase combustion chamber deposit to lower than 140% when compare to base fuel. Furthermore, a correlation between the Toyota 1G-FE engine IVD test and this fleet test is found.