1999 dodge ram 1500 valve rattle, 5.2 V8

I get valve rattling on acceleration with the use of regular octane fuel. high octane fuel eliminates the rattle. could timming be a factor?someone
said maybe a knock sensor? the motor has 145,000 on it, and is a 5.2 v8. any comments would be greatly appreciated.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
first we need to know if you have any oil consumption. there is a tsb on the 318 (5.2) for intake plenum gasket failure, this is a plate on the bottom of the intake and when it fails it causes oil consumption and spark knock (pinging) easy check. unplug the vac line going to your pcv valve (you want to plug this vac leak before starting the engine) leave the valve in so I fills the hole in the valve cover. then take the makeup air tube off from the intake, this tube runs from the other valve cover to the intake tube. start the engine, when you put your thumb over the hose you should fell positive pressure (air escaping as you remove your thumb from the hose) this is good, if you feel vacuum (negative pressure) then most likely the plenum gasket is blown, and needs to be replaced. its not a big deal you can get everything you need from the parts house and its a simple matter of removing the intake and putting in the new gaskets. also note that you do not want to run the engine long with the pcv disabled because of crankcase pressures and lack of scavenging, witch is what the pcv does.
and also for your information there is NO knock sensor on dodge truck engines of that family, this includes the 318 (5.2L) 360 (5.9L) 488 (8.0L v10) the new hemi and 4.7 as I understand it does have one but yours does not.
--
----------------------------
-Chris
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Go here: http://www.hughesengines.com/partDetail.asp?partID 698 I also started using Bardahl....gets my oil pressure back to where it is supposed to be.
--
------------------------------------------
Laszlo Almasi
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
First thing I think of is poor oil quality. Try Castrol 20W50. My last vehicle (not Dodge) had a nasty piston rod knock. Castrol was the only brand that quieted it. All the other brands were quiet for about two days.
--

Christopher A. Young
You can't shout down a troll.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Nah...in this case I guarantee it's the plenum leak. Although I agree with you and run Castrol myself (and Bardahl) the plenum leak exhibits exactly what he described.
--
------------------------------------------
Laszlo Almasi
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

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.