Fuel injector puller
 

I fought with pulling a bad injector for about an hour twisting and pulling - actually just tearing up fingers.

Small channel locks were the key!
You just have to be careful not to snap off the top.

Just wanted to share that tip.

Push it down with your thumb as tightly as you can muster, spray in some WD40 or even just use some gas (not as effective), then work it with your fingers up and down in the direction that you'd be pulling it out.

Often, I'll get a cut pigtail from the same type of injector and use that as ballast to pull it from more than one angle.