It has done it since i purchased it used...just recently did an oil change and i noticed it was a little more dramatic. usually goes away after the engine warms up. I would assume lifter a noise like that would be teh result of an oil starved engine or the oil not reaching the upper half of the motor soon enough. I've been running Mobile 1 5w-30 in it and change the oil regularly. IS there a different oil i should be using? or some sort of additive?