Removing my #4 was an absolute pita as well.
FIRST, USE AIR ETC. TO GET AREA AS CLEAN AS POSSIBLE!
This applies even if you're using The Tool because when you eventually do get the #×*% injector out, anything you DON'T get clear is almost certainly going to fall into the piston chamber!
My anxiety after that experience was part of my motivation to replace my head gasket, thereby permitting inspection & cleaning of the pistons & cylinders.
X2 on much PB soaking. Then, using a sharpie I drew a vertical alignment mark on the injector, then used a monster 1 1/8" box wrench on the threaded top of the injector to gently rotate back and forth in 1/8 turns (probably 50x). DO NOT REMOVE THE INJECTOR CAP!!! DO NOT TIGHTEN OR LOOSEN THE INJECTOR CAP, JUST SLIGHTLY ROTATE IN BOTH DIRECTIONS until the muck is loosened enough for the injector to be coerced-out (I gently leveraged a crowbar atop a wrench to protect the aluminum valve cover/intake assembly. Obviously, this isn't a great removal method, but lacking access to "The Tool" it worked for me).
However, be VERY careful to insure that the injector cap is realigned to the sharpie mark: that is a calibrated fit!!!
-clean the injector sleeve with a lint-free rag. To de-muck the sleeve and injector base I also used a flex-shaft screwdriver (without any tip installed; don't want to risk a tip falling off into sleeve) and goobed Vaseline on the end, making many fresh passes into the sleeve until the vaseline didnt get fouled. Seemed to work very well. But that was blind on #4; yours should be more forgiving.
-MAKE CERTAIN THERE'S NOT AN OLD COPPER CRUSH WASHER STILL STUCK AT INJECTOR-BASE IN HEAD!
Even if your injector still has its copper washer attached after removal, it's possible that a previous injector-service may have been less thorough. Again, Vaseline may help extract any orphaned washer, but those can be baked-in pretty firmly.
Obviously, you'll want to use a fresh washer and O-ring upon installation.
- It's way easier to install if you 'mate' the retainer crow-foot to the injector before lowering it into sleeve (obviously, you have to hold them together while lowering):
- The OEM O-rings are NOT indestructible so try to use measured force during installation.
- As a preventative measure, make a habit of periodically blow-cleaning the entire area around all four injectors.
- Couldn't hurt to also occasionally confirm injector retainer-bolt torques. If you catch one before it loosens to the point of blow-by you'll also prevent re-fouling the sleeve (this, from experience).