Mammad78

Hello
new member here, and sorry in advance for my grammar and spelling since English is my 3rd language 😊

2014 grand cherokee v6 3.6L
as the title says I’ve been struggling with this code p0304 “misfire cyl 4” for awhile now, tried most common 3.6L problems I found here and no luck.

things done in order

1- replaced cyl 4 injector / spark plug / coil with cyl 1. code came back same (p0304)

2- had small ticking noise so replaced all rockers, lifters and exhaust cam on bank 2 (same code again

3- did compression test all came in range (cyl2 145 / cyl4 145 / cyl6 150)

4- checked all wiring from pcm to injector and coil, no damage detected

5- opened cylinder head, refreshed with new valve seal and valve seat since nothing was wrong, valve guide was ok, leak tested it was ok, after installing cyl head back, my friend “p0304” came back 😂

i guess thats all what i’ve done , any idea what could be the problem?