MY RAV 4 - 57348 MILES. IT STARTED MAKING A TAPPING SOUND IN THE ENGINE AND IT HAS MAKES A METAL ON METAL VIBRATION UPON ACCELERATION AND ESPECIALLY WHEN I MAKE A GRADUAL LEFT TURN AND DECELERATE. I BROUGHT IT INTO THE DEALER. THEY SAY IT MAY BE THAT THE LIFTERS ARE A BIT WORN AND THAT THIS WILL NOT HARM ANYTHING. THIS IS ODD BECAUSE A NEW ENGINE WAS PLACED IN THE CAR AT 49,000 + MILES. THEY COULD NOT IDENTIFY WHAT THE VIBRATION NOISE WAS AND SAID THAT IT IS POSSIBLY A ROCK IN THE BRAKE SYSTEM. I KNOW WHAT THAT SOUNDS LIKE AND STRONGLY DISAGREE WITH THEIR ANALYSIS. THE NOISE IS DEFINITELY COMING FROM THE ENGINE. *NLM