2001 xk8 coupe 4.0. Replaced head gaskets due to water thru system out thru expansion tank then on to ground. Car never over heated and ran great with no codes. Water problem resolved. BUT engine now has rough idle and occasionally stalls and throws po341 code po300 301 304

new head gaskets( upgraded to metal style)
new octopus hose
New metal water pump
new radiator hoses
new spark plugs
new aluminum thermostat tower and tested thermostat
fresh oil and filter …..
Performed a hard reset….
batter has full charge ( new 6 months old)
placed vvt full retard with special tool. Cams flat , crank locked.
sliders and upgraded tensioners all looked great.



realized that I mixed up valve cover screws. Pulled and corrected to where correct screws are under cam shaft sensors.

Could I have ruined cam sensors with the installation of incorrect screws?

with engine running I can unplug cam sensors with no apparent engine performance change ( at idle) both banks.( sounds the same)

any thing I’m missing..
any help appreciated and thanks in advance.

 

It's possible as the ordinary cover bolts are slightly longer than the 'special' ones for the top rear of the cover. Should be easy to remove to confirm they haven't been impaled?

Here's the DTC text:



It's worth double-checking all the various loom connections you've had to undo.

 

99% chance it’s mistimed