well , I just aquiered my sisters 88 ls 2.6. Drove it from GA to VA 650 miles burned about 3/4 a quart, I thought that was high until I read this post. All I can suggest is check it EVERY time you get gas. No point in using synthetic, it does not seem to stick around long enough to be benificial....I wonder if Isuzu has an oil rig somewhere??? Stock in Mobile or Valvoline....My ls has 188k on it needs exhaust and hopefully mild work. I hope to get another 50k out of it, reminds me of the old army jeep....