Oil dilution: Gas mixing with oil. Inside of car fills with gasoline fumes. Dealers deny knowing about oil dilution. Internet says it can be caused by short trips - not allowing engine to fully heat up and burn off gas, 2) fuel injectors not functioning properly - pumping to much gas, 3) worn pistons and 4) other worn parts. Apparently there is no fix. I can get an oil analysis that tells the amount of dilution. IN the meantime the engine can lock up. Toyota dealer says its very expensive to check injectors, that they send them out and that they are suppose to last lifetime of vehicle.