Axioms were manufactured from 02-04, with the 04 model year having a direct injection engine that was never available before or after that year in any other Isuzu vehicle. I believe this may be the engine that Gussie mentions above, because it is NOT compatible with the VX due to the injection/ECU difference. As for oil consumption, my 04 Axiom burns oil WORSE than the VX.
IMHO the Isuzu 3.5 is flawed in all models and all years. It appears to be less so in late 00-01 VX's and perhaps 02-03 Axiom's, but that's not really been proven. I'd try to find a 3.5 out of a 01-02 Trooper as a direct replacement if it were me - there should be tons of those out there in junkyards.