In order to be ever more fuel efficient, the use of Direct Injection (DI) becomes standard in spark ignition engines. When associated with efficient turbochargers, it has generated a significant increase in the overall performance of these engines. These hardware developments leads to increased stresses placed upon the fuel and the fuel injection system: for example injection pressures increased up to 450 bar, increased fuel and nozzle temperatures and contact with the flame in the combustion chamber. GDI injectors are thus subjected to undesirable deposits formation which can have detrimental consequences on engine operation such as reduced power, EOBD issues, impaired driveability and increased particulate emissions. In order to evaluate the sensitivity of DI spark ignition engines to fuel-related injector deposits formation, a new engine test procedure has been developed. In this paper, the effects of gasoline composition on injector fouling are studied. Also the ability of the procedure to evaluate the performances of different Deposit Control Additives both in terms of reduction of deposits formation (keep-clean) and of deposits removal (clean-up) is discussed. In further aspects, the influence of fuel variability on the response of the additivation is highlighted.