9290 and 9F90 meter the ML in fuel 85-91 depending on the calibration the spray pattern is different the 9290 uses a 5529184 tip the 9F90 uses a 5229622 tip you need to change the 9F90,or better yet change all the injectors to 9G90's ,"F" is size of the spray holes ,"9" is is numbers of sprays,' the letter is the hole size, and the last numbers is the amount of fuel one can deliver, they have 3 setting for calibration "low, medium and high "you can send the 9F90 to Don at Quality Fuel Injection in CA and he can change it to the match the rest for around 60 bucks 209-863-8810