wierd intake noise???

[03ranger4x4]

Ok, idk what exactly cuased this noise to start up...becuase i just noticed it one day, its kind of easy to miss unless you listen for it. But i think it may have something to do when i changed my spark plugs...maybe..

the intake makes a like poping noise, but ONLY under very certain conditions. which are when I turn the key off, the intake makes a short pop right before the engine shuts off, and if you turn the ignition back on within say 5 seconds of the engine being off, it like makes a pop then hiss out of the intake... i have never seen this before, ever.

ALSO, i noticed today that it also make the poping noise when it is idling, but only when the A/C is on, it pops a few times when the a/c pump kicks on. then it will be quiet until it cycles back on.


sorta sounds like a back fire, but a quiet one. and it only happens in the above condtions. no other time. the truck drives and sounds perfectly fine when just idling without the a/c or driving at any speed.

 

[03ranger4x4]

update....relized the poping sound it made when you turn it off, then back on it cuased by built up vacuum in the manifold, i know this becuase when i turn it off, then press the gas pedal down, it makes the same noise....

Now, i need to figure out whats cuasing the high vacuum, which can explain why it idles a little rough, and bogs down and makes stupid noises when the a/c is on.

I think it could be a clogged pcv valve, maybe the idle control vavle is dirty aswell any thoughts anyone?

 

[powerranger262]

Mine just started this the other day after I cleaned my TB. The exact same thing. It doesn't seem like it's hurting anything, but why did it start doing it? I am also going to clean my idle control because it's time anyway. Make sure to post back if you figure it out.