Been there, done that. Mine on the WJ started in #4. After I put a new injector in #4, then #8 started. I took the fuel rail off again and did #8 and #2 for good measure while I was in there. That was five years ago. I have not had a misfire since then.
'06 XK Limited, 5.7L, QD II, Black, 163K
'02 WJ Overland, 4.7L HO, QD, Inferno Red, 126K