I have a 4.3L 02 blazer and i can hear a real fast rattle noise inside my cab, and when i got out to investigate i found that it appears to be coming from the hose/line that is coming up out of my driverside valve cover. The rattle comes and goes if you rev the motor it stops for a second or so and then starts again. Any clues what this part is or why it would be doing that? Thanks!! PS. tried search and didn't find much . . . . . .

 

Not sure as my 4.3 is different with the additions I have on it now but isn't that the PCV valve? Take a pic or 2 & post em. One of the engine bay & one closer up of the part. If it is the PCV they should be under $20. I know they rattle when you take them out & shake em.

 

there is a plunger in there that moves up and down, it may be touching your throttle cable. can you feel the vibration on the gas pedal?

just zip tie it or something out of the way....