Personally I use a product called seafoam and inrtroduce it through the vaccuum system as well as the feul tank with great results. When I had to pull my intake to replace the gaskets, it was almost as clean as the day it was first assembled. if this speaks for how well it cleans, then my injectors should be just as clean. I use this stuff in the method described once a month. hope this helps. It runs about $7.00 a can, but it's worth it to me. I also use it in my 94 saturn and my 91 toronado. The saturn is at 200,000 on stock injectors, and the toronado at 315,000 also on stock injectors.