backfireing in exhaust?

What would cause what sounds/seems like backfireing in the exhaust at high rpms (4k range)? It's the best my Dad and I can figure my truck which is a NBS 99 Silverado
5.3l At high RPM it makes this really nasty poping sound from under directly under the truck. Any ideas?
Adair
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Is the sound occurring while setting still or while moving?
--
Steve Williams
Near Cooperstown NY
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Never tried revving it that high just sitting there.. this always happend when moving... and normally it takes a second for it to start... eg, after the tranny down shifts and it's good and locked in..
Adair
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You have checked ALL the U Joints correct? (4x4 check the front axles also) Try it through the gears manually and see if it occurs at the same RPM ( that will tell you if it is engine/converter related) If not then it is probably in the driveline.
--
Steve Williams


"Adair Winter" <drummer snipped-for-privacy@mail.com> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
ok, thanks!

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
have you changed your fuel filter lately
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Wrong spark plugs can cause this.......
wrote:

--
elbert.clarke@**us.army.mil
remove the ** to email
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

wrong as in how? just flat out the wrong type/brand of spark plug? please do expound. because I do need to do plugs and wires. Adair
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I've seen this happen on a truck that some &$^% put champion plugs in. Make sure your GM truck has A/C delco plugs of the correct type.
On Fri, 27 Aug 2004 12:39:46 GMT, "Adair Winter"

--
elbert.clarke@**us.army.mil
remove the ** to email
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Very true... The only things I'll ever use Champion spark plugs for are my lawn mower or outboard motor.
For the older, pre-platinum spark plug engines, I always use the plain ol' black base AC plugs. If it originally had platinums in it, then use AC platinums. The'll last forever.
Tony

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I have AC platinums in it now but they are old but not real worn.. i just want to change them so i know when they have been done.. Arn't there several versions of the AC Delco Platinum plugs? What works best for my 99 5.3?
Adair
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

It was changed not to long ago... can't remember but i have it wrote down, less then 10k ago and it was doing this before.
Adair
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

btw, why?
Adair
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Related Threads

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.