car would barely run at times, other times it was fine, took to toyota dealer and they replaced bad plug wires, car still had same problem but was worse, took back and now they are telling me cylinder 2 has a bad fuel injector. They say if you replace just one, it will definitely be back shortly with another failed injector, they want $900 to replace all 4, and $600 to change one. Called around to several local shops, and all gave same story? Doesn't make sense to me how one new one could effect the other injectors. any ideas appreciated.

dealer replace all four injectors for $900, car ran good for two days and now it is running just as bad as before, barely idleing and extremely sluggish, dealer has had it for a week and called and said it runs like crap and isn't giving any codes and they can't figure it out. for fun they tried changing the iac valve and the maf, but neither made a difference. It seems to be worse when the ambient temperature outside is warmer. help!! thanks in advance

They should have checked the fuel filter, right?

I doubt it is a fuel problem. Try replacing the coil. They are the weak spot in the ignition.