Engine Rattle at 3000+ rpm

[flash319]

I have a 98 1.9 in a Jetta.  It is bone stock.  I put a new turbo on it when I bought it.  Has 340km on it.  It runs good but when you get to 3 grand on the highway you can here the engine start to rattle like when it is cold.  If I give it more fuel then it goes away until you let off again and just cruise then you can here it.  

I am thinking lean condition but how do I adjust it?  Max fuel setting adjustment?  Any ideas? It is not that bad but can deffinatly hear the  engine change at 3k.

[jtanguay]

Could be nearly anything actually.  My car seems to have this weird rattle at around 1500-1800 rpm, but its something in the body.. (plastic or whatever).   3k rpm sounds like either 5th gear, motor mount, cv joint or something like that, since you say when you apply torque, thus adding pressure it goes away.  You sure its not bad tires or alignment?  I would think that if fuel was off and/or timing, that low rpm idle would be rougher.

[TDForNow]

Light fuel high RPM "rattle" could be too much timing advance

Alain