I bought my 99 Prizm 1 month ago after much searching. It was very hard to find a Toyota with a really clean looking oil cap. This one had some varnish and 112K (not bad for here). So I went about baselining it. tune up oil change and Auto-RX. After 1k I added half a quart. no problem. I've put another 700 miles figuring I'd change it this weekend. Just happened to check oil. None on dipstick!! I immediately added a quart. I figure I was down a full quart and a half. I changed it today and I am wondering what to make of all this. Is this kind of oil consumption normal with ARX?