Strange noise under light throttle

[rtuck1]

Under light throttle at about 25-30 mph a noise becomes present, its a fast rattle that sounds almost like a loose heat shield but it only does it at this particular speed. Any suggestions or anyone else had anything like this come up?

 

[Veritas]

Considering all of the mods you have made to your car (listed in your sig) it could be caused by any of those things.

 

[gm350reratliff]

Sounds like engine ping. Try using all the fuel in your tank then filling up at a different fuel station. Maybe a different grade of fuel as well. I hear it sometimes in my 4runner too. I wish I could check the quality and true octane value in the gas before I fill up because I sometimes think we are not getting what is really advertised.