2004 Gmc Sierra

[sdgmc2004]

hi I have a 2004 GMC Sierra 5.3 with 110,000 mi, when my rpm's reach about 2,000 i hear a knocking clicking noise. Is this bad? what could it be? any and all comments would be awsome, thanks dustin

[jro909]

could be injectors, lifters....more then likely an exhaust leak

[sdgmc2004]

could be injectors, lifters....more then likely an exhaust leak

If it were an exhaust leak wouldn't I hear it at any rpm? I only hear it at 2000rpm right before it shifts. Any ideas on how to diagnose if the injectors or lifters are bad? Thanx for the comments

[jro909]

yes you should be able to hear an exhaust leak throughout the rpm range but it would be more profound at higher revolutions, when i said lifters/ injectors i ment just the noise if they were bad you would have other issues besides sound

[GMstrong]

yea i got the same thing on my 99 sierra mine has a leak around the cat because i see moisture dripping from that area sometimes.put the put the emergency brake on and throw it in drive pop the hood and give it some gas see if its coming from lifters or injectors if you dont hear the tick under pressure from under the hood then obviously its an exhaust leak.

[SouthCo]

Does it do it when cold and when the engine is warmed up? 2000 rpm is not that high. I have a little over 180,000 miles on my '03 Tahoe with 5.3 and it's still pretty smooth. At first start up if I take off, I hear a little tapping for about 15 seconds.

[sdgmc2004]

The noise happens when the truck is cold or warm. and the noise can only be heard when the motor is right at 2,000 rpm. all other rpm ranges have no noise. I'm going to sheck for exhaust leaks today. thanks for the comments guys, keep em coming

[sdgmc2004]

I cant find an

The noise happens when the truck is cold or warm. and the noise can only be heard when the motor is right at 2,000 rpm. all other rpm ranges have no noise. I'm going to sheck for exhaust leaks today. thanks for the comments guys, keep em coming

 

i cant find an exhaust leak anywhere....aaarrrrggghhh! what to do now????

[05GMCZ71]

only thing left that I can think of is to take it in to have it diagnosed.

[RaddHazzard]

Maybe check to see if you have all of your exhaust manifold bolts. They rust and sometimes the heads break off, creating an exhaust leak.

[jro909]

yes i had a bolt break off one of my manifolds and you coulden't see it without really getting down in there along the firewall

[sdgmc2004]

yes i had a bolt break off one of my manifolds and you coulden't see it without really getting down in there along the firewall

 

will try to check on fri, thanks for the input guys