When I stop at a stop light or any stop for that matter, I hear a rattling sound. It kinda sounds like it's coming from the dashboard somewhere cause it's too loud to be beyond the firewall. It's kinda like a deeper rattlesnake kinda sound, it's hard to describe. Sounds like something is loose at vibrating really fast. It doesn't happen while I'm driving, only when I'm stopped and the truck is idleing. Any ideas. Next time I get a chance, I'm going to pull the cover off the gauge cluster and see if anything is loose. Gotta install my glow gauges and my bezel when I get one.

 

There's a possibility it might be beyond the firewall, I heard a harmonica sound when I was in passing gear and SWORE it was inside my dash, but turns out my transmission fluid was a little low it made that noise, weird huh?

Sorry I'm not much of a help, I suck at car stuff! Just thought I'd throw in my cent-and-a-half, LOL.

 

Yet another "not knowledgeable" guess, but do you have anything in your glove box that would rattle around? When my small ice scraper was in mine it made a racket until I figured it out and took it out! But I have a goofy idle anyway so that probably didn't help....

 

Does the truck seem to vibrate more when stopped?

 

Take a look under the hood. Specifically at the PCV valve line (driver's side valve cover) and it's proximity to the throttle cable.

 

It shakes a little when it idles. A freind of mine's brother drives the same model blazer and he said that it's about the same idle in his too. The difference what mine will do is it will idle normal, but then it sounds like it idles high for a few seconds and this is when the rattling occurs. I just thought of this. Sometimes the rattling noise last for a while longer than others, but most of the time, it lasts for about 3 seconds at a time. I'll check the pcv valve tomorrow. Thanks

 

Have you checked under the hood while idleing anyway? Get a mechcanics stethascope and see in you can get closer to it that way and it ight just show itself.... You can control the throttle from there too to see if you can make it go away and when it does.

 

Good suggestion Kyle, I was thinking the same thing as I was reading down through the posts, and of course you beat me to it..lol....I remember the first one of those I fixed (back in 2000) that guy was soo happy! Just like the dozen or so I have fixed since then...lol I did notice that that particular problem (with the PCV hose rubbing the Accelerator cable) was alot worse when the engine was cold.

 

now that you mention that fact lastcoupe, it does it more in the morning in the first 1/2 hour of driving. I'll check the pcv valave tomorrow. You said drivers side valve cover-would it be loose or something. Is it just something that needs to be tightened or is it a hose that i can replace.

 

Hey i might have idea for ya is it just when you come to a stop?On my 98 i have a bad multifunction switch and when i stop the relay under the dash clicks like crazy havent fixed it yet but soon..It is loud to and repetitive like a rattlesnakes rattle.hope this may help.