oil consumption is fairly "normal" for a vx... some people burn as much as a quart every 1000 miles, so burn none at all... mine goes back and forth, but is usually about 1 quart every 3k miles

check engine light could be a huge variety of things from messed up speed sensors to your gas cap not sealing properly to a dirty maf sensor to a stuck egr valve, the only way to tell is to have someone with a obdII scanner check it, you can buy a scangauge which you can get for about 170 from www.scangauge.com or you can go to autozone and have them read it, most will read it for free... dont go to a shop, they will charge you 75-100 just to read it and tell u what it is.. good luck