you might also want to check fuel pressure, at idle a low fuel pressure will keep you running but starve out undr a load. I think your load pressure should be between 14 and 20 lbs. of pressure. and 30 lbs in an uncharged system.
mine: 95' YJ-4"lift (Skyjacker) 2" body lift. chevy 350/th400/np241 swap. herculined interior, boat drain plugs for floor. TJ hood. 33" MTR. Up next: bigger axles.