I'm getting the following codes:

P 0363 misfire detected, fueling disabled.

P1343 misfire cylinder 1
P1345 misfire cylinder 2
P1347 misfire cylinder 3
P1349 misfire cylinder 4
P1355 misfire cylinder 7
P1357 misfire cylinder 8

What I have done:
1. Replaced all spark plugs (no oil found in the spark plug holes)
2. Changed the valve cover gaskets

X is running very rough and not idling properly. Not sure where to go next.
Either coils, catalytic converter, Air pump control valve, camshaft, oil seperator, fuel filter.

Suggestions would be greatly appreciated.