99 silverado noise at higher rpm

Normally tiney rattley noises are just heat shields that have come loose check under the bonnet and under the car for loose heat shields also the heat shield around the cat can corode and come lose hopevthis helps ivan

Sounds like car has been overheated and has a collapsed piston skirt. This will cause piston slap until piston heat up and expand.-------------------------------------------------------------------------
vas 5054a

The rattle is caused because the rpm is lower. When stopped in drive with one foot on the brake, press the throttle down slowly until the vibration stops and the noise goes away. Cause? Weak or bad motor mounts, loose bolts or parts.

Sorry for the late reply but, no, it is not related to a loose heat shield. It is a louder rattling sound more like a loose bearing vibrating inside either the transmission or the clutch assembly. Only between 1600 and 1900 rpm. and it is not present under ou over these rpm. The rattle desappear when I lock the 4X4. Dealer is out of solution!!

sounds like your fan clutch may be failing, remove the drive belt and manually spin all the pulleys by have listen for noise and feel for looseness in the bearings

I just went through a similar problem with mine. Try plugs and wires first. Go have someone check for codes if the check engine light is on. If it throws a catalyst (cat) code you need catalytic converters. Just had mine done and its running better than ever. Good luck.

catalytic high temp shield protecting bottom of car from the high heat. it maybe cracked or bent and is vibrating on the cat at certain rpm's. easy fix bend it back or away enough to prevent contact AFTER IT IS COLD

sounds like a bad cat. converter. it could have some pieces of it rattling around anywere between cat and muffler.
also i have a ford ranger that did the same thing and i could not make the noise happen by banging etc i pulled my hair out because it was a short lived but loud noise at about 1500 rpm. finally i got some bailing wire and wrapped the heat shields with it one at a time.test drove and the noise did not vanish but it was greatly reduced. sure enough the heat shield on top of the cat had a spot weld that broke. took it to midas and had weld it up for me.

sounds like you have something loose first track were the noise is coming from and inspect the area for loose componets if it is coming from your motor then you might need a mechanic to check it out could be something loose in there

try replacing your EGR Valve, or your Oxygen Sensor