Typical for a YJ/TJ. So check the lines are good not collapsing when hot. The system takes fresh air from the box into the engine. Then sends any oil vapors back to the intake to be burnt. A closed system.
Fix us easy clean hoses all connected good PCV/ CCV. There ae in some valve covers a baffle which may need to be cleaned so it can breathe.
Also your oil level is critical. Too much and it will blow everywhere. Also your oil cap may need to be replaced. The seal shrinks and is no longer I able after many years. They are cheap and available most Jeep sites Qtec and Morris.
89 2.5 TBI, 4" RC lift, 1" Booms, SYE, Adams Driveshafts front and rear, Ford 8.8 with 4:88s, BFG 33X12.50X15, and a ton of other stuff.
AF Jeep Club Tail Number 184