My '99 w/ 72.000 miles has burned 1.7 quarts of oil during the past 600 miles of driving - mostly interstate, no off-road, no hard-pushing. I don't care what Isuzu says, that's excessive consumption. I had switched on the last oil change to a 10w-30 full synthetic. Today I went with a regular 15w-40. I'm thinking I need a heavier grade oil that won't blow past the rings as easily. At any rate, it's going back to the dealership on Friday to be looked at. If it can't be fixed, they'll have to buy it back from me (have had it less than three weeks). Love the vehicle - don't want to have to drive with one hand on the wheel and the other hand holding a quart of oil.