Rough idle, rumble in air box, no codes

[vekasy]

2003 V8, 87k miles, original plugs. Checked for vacuum leaks, cleaned MAF with contact cleaner and air. There was a minor improvement after computer relearn. Installed a new after-market IAC (Duralast from AutoZone $85). Did computer relearn. Result was highly erratic idle and RPM ‘sailing’. Considered a defective part. Exchanged IAC for same. Same result. Installed the old IAC and idle returned to the original issue.
Could the IAC not be getting a proper signal?
Thanks much!

 

[matt0248]

Well, I replaced my IAC last year due to a failure of the original one. I also replaced with an AutoZone one. I have noticed the same thing, especially when the engine it hot, the idle is a little rough and it hunts a little bit. I cannot put the old one back on to try it because it is bad. I have been toying around with buying a new Motorcraft one to try it. I wanted to try to clean my TB first but have not had time.

 

[05explorerXLT]

Yes aftermarket IACs are notorious for not working straight out of the box. Stick with buying one from a ford dealership.

 

[GearHead681]

If the IAC was not the culprit of the original issue (rough idle, rumble in the airbox), what was the problem/fix? I have the same issue with the rumble in the airbox, hanging idle and no codes. What causes the rumbling sound in the airbox???

 

[speedball]

If the IAC was not the culprit of the original issue (rough idle, rumble in the airbox), what was the problem/fix? I have the same issue with the rumble in the airbox, hanging idle and no codes. What causes the rumbling sound in the airbox???

Same issue with mine. Anyone have any comments on the air box rumble?

 

[GearHead681]

Same issue with mine. Anyone have any comments on the air box rumble?

It turns out that it WAS the IAC in my case. Just hard to imagine how much the air intake tube amplifies the sound that the little IAC makes! I took the recommendations of others here to buy a Motorcraft branded IAC and got it from Rock Auto. I've been living with that weird rumbling sound for a year, kept getting worse over time where I couldn't stand it any more. Now on to the next weird sound my Explorer makes