unless you bought your VX new from a dealer or bought from a family member who was the original owner.. your VX is out of warrantythey had 10 year 120k mile warranties in 00 and 01.. which cut in half upon sale to a non-family member
as for the check engine light.. what is the code? a lot of people have issues with their EGR valve causing check engine lights but iirc the code doesnt necessarily reflect that thats the problem... also when replacing the timing belt.. look around there are a few TSBs (technical service bulletins) that correct the timing belt replacement procedure as well as the torque on the intake manifold (the intake manifold gaskets might be leaking due to a mistake in torquing the bolts.. that could cause a check engine light too)
oh and i burn about 1 quart every 3k miles using mobil 1 synthetic.. but it all happens fast.. like i will be fine for 1000-2000 miles then all of a sudden 500 miles and ill be 1/2 quart low.. i just check every gas fillup and keep a bottle of oil on hand so that i can keep it right on the full mark at all times.. if you pay close attention you can spot warning signs.. im to the point where i swear i can hear when my VX is running low on oil