I used Redline SI-1 Complete Fuel System Cleaner. That stuff took care of clogged/sticky injectors that had been off a junkyard motor and sat around a garage for who knows how long before I installed them. The car would hardly run before I dumped a bottle of it in there. After running a tank with a bottle of SI-1 in there they cleaned up perfectly and started throwing CELs (for too much rich correction - which is expected when going up in size, but I wasn' getting before the cleaner).
This product is the first time I have ever noticed any difference using a gas additive fuel injector cleaner. I picked it up at a local Pep Boys for about $5. Highly recommended, at the very least it will rule out a possible cause for not much money. Might want to change your fuel filter if it has over 30k miles on it, too (then run the FI cleaner - no sense in wasting it on a clogged/dirty filter).
