Got a PO353 and a PO356 what does this mean on 1999 Ford Expedition

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Changed Coils all 8 and spark plugs
Didnt have this problem before
Also getting a misfire
(2) Answers
(3) Comments
Check wire connections at coils # 3 & 6 possible damaged, loose connector. Check for cracked spark plug insulator, same cylinders 3 & 6.
# 3 is 3rd cyl from front on pass. side, # 6 is 2nd cyl from front on drivers side.
should get compression check. possible may be loose spark plug or fouled threading. these engines have a shorter thread count which has caused several issues varying from vehicle(spitting plugs, spark plugs snapping during extraction, thread slots that are brittle and prone to cracking, etc).