Just got a 2003 with 170,000 miles and there is a rattling sound from the engine that seems like a timing chain. No related codes stored. I took off the drive belt to make sure it wasn't coming from any of the pulleys and it's not so it's inside the engine. Took off the valve cover and and checked the play in the chain and it seems fairly tight as far as I can tell. Removed the spark plugs and turned the engine over with a wrench on the power steering pulley. Hear a clickity clack noise down low as I turn it over. Any ideas. Chain tensioner?

 

could be as simple as ur valve gapping or the piston hitting the valve possible u can submit a video of the sound? because i had the same issue when i bought mine 6 months ago and just ignored the noise after getting the OK from my mechanic.

 

It was a bad oil pump chain tensioner.