I own a 3.4l 2002 sr5. About two weeks ago i had an oil change and filled it up 5 quarts no problem. A few days after the oil change i went on a road trip-ended up putting around 1500miles on it, however during the middle of the trip when i checked the oil it was gone. Vanished didn't show a drop of oil on the dipstick, and this was only after about 800 miles of driving on the interstate after the oil change. Thinking the obvious i checked for oil leaks. Nothing. Checked for oil burning on the exhaust manifold. Nope. Did not smell any burning oil anywhere in the engine or near the exhaust. Moreover, i never get blueish smoke from the exhaust. So i drive to some oreilly 600 miles from home and grab a couple quarts of 10w-30 drop it in the engine, check the dipstick, and still not a single drop of oil. SO i grab THREE more quarts and come to find there was ZERO oil in my engine. I have absolutely no clue how i did not sieze during 800 miles of driving with no oil. Drive on the new oil for 250 miles or so, check dipstick, and what do you know its empty again. Someone please tell me how 5 quarts of oil vanishes from my engine in 250miles with no oil burning or leaks. Im beginning to develop a theory that 5vz fe's just don't even need oil, i mean hell i might as well drop whatever i want in the engine. Maybe it just needs some water or coolant in there.