In 1998 , Toyota 's D4 direct injection system first appeared on various Japanese market vehicles equipped with the SZ and NZ engines.    Toyota later introduced its D4 system to European markets with the 1AZ-FSE engine found in the 2001 Avensis .  and US markets in 2005 with the 3GR-FSE engine found in the Lexus GS 300 . Toyota's 2GR-FSE V6 first found in the Lexus IS 350 uses a more advanced direct injection system, which combines both direct and indirect injection using two fuel injectors per cylinder, a traditional port fuel injector (low pressure) and a direct fuel injector (high-pressure) in a system known as D4-S.  In 2015 Toyota added a self-cleaning cycle idle for the direct fuel injection, the system only operates during idle with a maximum 10-minute cleaning cycle.