I have used witchhunter several times to clean/service injectors. http://www.witchhunter.com/ I wouldn't hesitate to use them again. $22 per injector. Last time I used them I sent the 4 (2 from a junk yard) and they matched them within .9% of eachother.
I've used Witchhunter before and they are awesome!! Shipped mine on a Monday and on my door step Friday!!