Engine Noise - Valve Chatter?

[joneill1975]

My wife's I35 started making this noise this past week (see videos). It does it when you first start up. The noise subsides once it is warm, but it still does it at different points throughout the RPM range. You can hear it better in the second and third videos. Can anyone tell me what this is? Is it valve chatter or something else?

[youtube]http://www.youtube.com/watch?v=JTND79vTRRs[/youtube]
[youtube]http://www.youtube.com/watch?v=rQzc-5D2_TQ[/youtube]
[youtube]http://www.youtube.com/watch?v=u5nFi6bDX-4[/youtube]

[4cefed]

Wow.... The audio is pretty horrible but could that be an exhaust manifold leak? As things warm up and metal expands, the noise could lessen.

And stupid question, but you have checked the oil level right? If your valve lifters aren't getting enough oil pressure, that could lead to some horrible noise like that. It's kind of hard to figure out what that is with that audio quality. Have a trusted shop nearby? That could be serious.

[loystock]

Do you change oil regularly? A BG Quick Clean before oil change and a bottle or two of Fuel System Cleaner like Redline SI-1 may help (make sure the fuel system cleaner has PEA in it).