If the DTC came back on, you still have a problem. You have changed the coil and spark plug, other possibilities are a small vacuum leak or an injector problem. First I would run a compression test while the engine is hot. If compression is good on cylinder no. 1, I would swap the new coil and spark plug and the injector to another cylinder and see if the problem moves to the swapped cylinder.
_________________
Supporting Vendor and Moderator of LOST05 Jeep Liberty CRD Limited
Ironman Springs/Bilstein/Shocks
Yeti StgIV Hot Tune
Week's BatteryTray
No FCV/EGR
Samcos/ProVent
SunCoast/Transgo
Carter Intank-pmp
2mic.Sec.Fuel Filter
Flowmaster/NO CAT
V6Airbox/noVH
GM11 Bld.fan/HDClutch
IronrockArms/wwdieselMount98 Dodge Cummins 24 Valve