since the ltft's go up with rpm's, don't think it's intake leak related.
probably gonna be fuel delivery related: clogged or dirty fuel injectors, dirty/clogged fuel filter, dirty fuel filter sock, or an exhaust restrictions such as a clogged catalytic converter, or pinched exhaust pipe section.
burning that much oil through the cat, i'd check that out closely. graph out the downstream o2 and see if it mirrors the upstream. if so, the cat's bad.