Just pulled my injectors after 4 yrs ( I know I should have done this long before ) and this is what I found . Kind of gummy residue , wiped off pretty easy , sending out for cleaning . I'll post before and after results. These are 120lb injectors and I was at 82% duty cycle on a 10.3 @129mph pass , 30psi. Make it a habit to have your injectors cleaned in the off season or once a year.