exact same thing happend to me in my s10....turns out it was just a loose bracket... it check them all

 

A lot of newer cars, especially GM, are having trouble with constant piston slap because of the wide use now of high-silicon content pistons. The percentages off silicon vary from batch to batch and the piston to wall clearance dosent.

 

If it does it consistently I'd take it to the dealership and show them the problem. That's the joy of owning a new car with a 10 year/100000 mile warranty.

 

yeah, im think its the vtec as well.


no really, check the heat shields.

 

sounds like the 2005 should still have warranty. i would take it in.
could be a shifter, heat shield, exhaust mount etc...