I had the same issue. Tank built pressure and blew out the diaphragm on the fuel pump and filled my oil pan with gas.
I'm installing one of these to help fix it. It's a roll over valve and a vent line. I'm reinstalling the entire system.
88 YJ 35's 8.8 rear, family style roll bar, ax-15 external slave conversion, Custom double D fab dash 4" of lift taurus fan, Head light wiring upgrade, MSD 6al, JB conversions SYE, 258 with RV cam, Long tube headers, Borla exhaust. 1"mm, Auto meter gauges.