Nope. All changing injectors will do for you is screw up your idle and give your ECU fits. You don't even need a AFC yet, the stock system is more than capable of handling the mods you have. Unless you change cams or get nitrous or FI, it's a big waste with more negative than positive effect.

EDIT: Oh yeah, the CEL could be from yoiur eCU thinking your injectors aren't flowing properly. Try disconnecting or disabling the AFC and see what happens. In the meantime, consider getting a Cobb or Ganzflow intake, the Weapon-R is poop.

EDIT EDIT: Unless you just really really want the sound, then who is gonna miss 3 hp?

 

No, because of something called "injector pulsewidth." the injector turns on and off really really fast in order to keep up with the speed of the piston flying up and down in there, but it still takes a certain amount of time. Call it 1 second. At lower RPM, it would require turning on the injector to flow for less than that time- but, it can't physically be open enough to flow fuel for less than one second. Because of this, you get too much fuel for the amount of air flowing into the cylinder. Now, when he slaps a spinny muffler on there (that's a technical term ) and puts more air in that cylinder, then he can actually increase the on-time of the injector (which is basically what an AFC does, by manipulating what the ECU is "seeing" from the inputs of various sensors) to reach the proper mix of air and fuel. For these same reasons, smaller injectors can "starve" really high-flow or high-boost engines by not being able to stay open long enough to supply enough fuel for the amount of air. And that is much much worse than running too rich, at least at small margins.

 

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