new noise after IAC cleaning

[George Doogle]

01 with 55K. Noticed rough idling lately that felt like the engine would surge then drop off. I noticed the project on cleaning the IAC and gave it a shot. The cleaning went fine and even cleaned the throttle body while I was at it. Made a big difference in starting the engine, the idle, and general performance. HOWEVER, right after the cleaning I did my weekend chores that involved about 20 miles of driving. The truck ran great. But when I pulled into the driveway I heard a sound that I can only describe as sounding like a tennis ball bouncing in a five gallon bucket. If I sit in the truck with the engine idling I can hear this sound about every 30 seconds or so, and it only last for a second or two. Under the hood I traced the sound as coming from breather box back towards the throttle body. I know this isn't much to go on, but I'm wondering now what I could have done. Any one got any ideas? One suggestion was that the cleaner could have damaged the rubber gasket in the IAC so I've considered replacing it.



Thanks,



G

 

[Kevin Palmer]

Noises that come out of the Air Box and throttle area are normally a back-fire type casue....



Not sure how that could have happened doing the cleaning you did. Did you allow a large amount of liquid to go into the intake by chance? If so, once it went into the cylinder you could have caused some sort of a mechanical breakdown as liquid can not be compressed (to speak of).



Even so, you would not have bent a valve and back fires are more often valve oriented....



Hmmm

 

[George Doogle]

I don't think/hope much fluid could have gone into the intake. I sprayed cleaner with the butterfly valve closed and wiped out the inside. If there was a mechanical breakdown wouldn't there be more obvious sounds and issues? The truck runs fine and sounds good, it's only when idling that I hear the noise and I don't hear it everytime it idles.

 

[shawn stonbraker 2]

Mine does the same thing. I have an AM filter kit on mine and just when it's idleing it makes that sound. I have racked my brain as to the cause and no findings. Hopefully someone knows what it is but mine has been doing it for quite some time and no problems or codes. So, if nobody knows, you're not alone on this one.

(By the way, mine was doing it BEFORE the IAC cleaning. That was why I did it.)

 

[George Doogle]

Thanks Stone. At least I feel a little better now. I wonder if mine was making the sound before the cleaning and I just never noticed it. I was planning on doing more investigating under hood this weekend in hopes of finding something loose.

 

[Todd Z]

What your hearing is the IAC valve popping open and closed correctly....

Do this....

after driving, shut the truck off, then turn the key to the run position but do not start, you will hear a huge POP and suck of air... Thats the IAC doing it's job....

Todd Z