2017 unlimited sport 3.6L
45k total miles, bought used from dealership at around 30k.
Had a check engine light and rough sounding idle so I took it to a shop to get diagnosed -

PERFORM CHECK ENGINE LIGHT DIAGNOSTICS FOUND FAULT CODE P0303 IN ENGINE CONTROL UNIT
PERFORM ELECTRICAL TEST TO CYLINDER 3 IGNITION COIL FOUND GOOD POWER AND GROUND AND RESISTANCE WITHIN SPEC
SWAP COIL WITH KNOWN GOOD COIL FOUND MISFIRE REMAINED ON CYLINDER 3
CONNECT VACUUM GAGE AND MONITOR VACUUM AT IDLE FOUND REGULAR TIMED DROP IN VACUUM AT SAME FREQUENCY OF NOISE FROM SAME AREA FOUND
POSSIBLE LIFTER OR VALVE SPRING BROKEN RECOMMEND VEHICLE TO DEALER FOR TEARDOWN AND INSPECTION FOR POSSIBLE HEAD REPLACEMENT

Tried calling my dealer to figure out if my warranty would cover this but got no answer, plan on bringing it to a dealer anyway. I know they extended the warranty for this issue for 2011-2013 but just looking for any other sort of advice or information on this that I may have missed in my google searches. Thanks

 

Usually the way it works is you have to bring it in, they diagnose and will advise you it's covered under warranty. Telling them you've been digging into the Jeep will void the warranty.