p0304 code rough idle until its warmed up then appears to be ok???

P0304 is misfire cylinder 4 means. I would look at your intake manifold for a possible leak or even the vac system for a leak. DO NOT DO THIS FOR A HOT MOTOR/ENGINE THIS CAN BE DANGEROUS AS CALIBRATOR CLEANER IS HIGHLY FLAMMABLE. take carb cleaner start the jeep quickly spray around the intake manifold if the motor sound changes or dies you've found your leak. Be responsible you can ignite your car and I'm not responsible if you do.