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Discussion Starter #1
Ok so about a month ago i start hearing this whining noise from under the hood and its like an on and off kind of thing. sometimes you hear it and sometimes you don't. and recently my idle has gotten really low, somewhere in the 550 rpm. the computer catches it and keeps it from stalling, so it jumps up and down. That whining noise is gone but the idle is low so I have read that the low idle is from carbon building up in the IAC so today i got a can of carb cleaner and cleaned everything out of the IAC. Started the car up and ran great for a few minutes, drove it around the block for a while and ran like a champ, idled at like 700rpm. drove into my driveway and the idle became low again and that whining noise has came back. I'm wondering if that whining noise is from a bad IAC motor or something else. Any advice? Thanx :cooldude:

By the way, when i removed the IAC to be cleaned, i found some dark liquid in there. It smelled like motor oil. Any ideas of how it got there? same color and smell as motor oil :?:
 

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Ok so about a month ago i start hearing this whining noise from under the hood and its like an on and off kind of thing. sometimes you hear it and sometimes you don't. and recently my idle has gotten really low, somewhere in the 550 rpm. the computer catches it and keeps it from stalling, so it jumps up and down. That whining noise is gone but the idle is low so I have read that the low idle is from carbon building up in the IAC so today i got a can of carb cleaner and cleaned everything out of the IAC. Started the car up and ran great for a few minutes, drove it around the block for a while and ran like a champ, idled at like 700rpm. drove into my driveway and the idle became low again and that whining noise has came back. I'm wondering if that whining noise is from a bad IAC motor or something else. Any advice? Thanx :cooldude:

By the way, when i removed the IAC to be cleaned, i found some dark liquid in there. It smelled like motor oil. Any ideas of how it got there? same color and smell as motor oil :?:
Sounds like it could be the IAC, but could be a vaccum leak of some sort (although that would raise the idle up, but the computer might be bringing it down)

Have you done a code scan?
 

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Discussion Starter #3
Well the check engine light isn't on. As for codes how do I do that? I don't think it's a vacuum leak or else that whining noise will be contiuous. This whining noise is on and off. Comes on only when it idles. When I rev it it's gone. Today I drove it in the morning and it was idling great and when it warmed up the low idle came back.
 

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Discussion Starter #4
Sry I forgot to mention that it feels and sounds like the computer is struggling to bring the idle up. It drops to 500rpm and the computer fault he's that it's about to die and it struggles to bring it back up to 600rpm
 

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motor oil in the idle air valve ???? you might need to clean your egr valve also i mean where else would it come from .. give a look at your pcv too its like only $2 and it can ruin a good idle
 

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Discussion Starter #7
Thank guys for the help, i will go do that in the morning. I hit up the junkyard today to find an IAC. All i found were the engine block with the intake and valve covers gone. I just want to point out that it runs fine up until like 15 mins and the idle drops suddenly. I think the IAC motor is just overheating and dying. Not completely sure. i will do the diagnostic test and see what happens. thanxs guys!
 

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Discussion Starter #8
i have a 1991 mustang GT 5.0 HO..... this is a two code not three code rite? just making sure. Thank You!
 

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Yes it's a 2 code aka OBD1. A scanner can be had for about 30 bucks or you can do the self test listed above.
 

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Discussion Starter #10
where do i get that scanner? would save so much trouble LOL. i mean the paperclip works the same, but the scanner would be more accurate.
 

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Discussion Starter #11
so i did the self test and i got these codes, i got 13 as one of them the first time i tried it when i just finished running the car. didnt read the rest of them because i lost count.

i waited like 40 mins and then i did the test again for the KOEO, i got codes 33, 41, 91, 96

for the KOER i got 21, 41, 91, and 33

21 code is regarding the coolant sensor and that one should be accurate because my low coolant light is always on (either on or off, its random)

for the other codes, what is wrong?
 

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Go to fordfuelinjection.com the 2 digit codes are listed there. Good reading.
 

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Discussion Starter #13
thanx msally. i have a question, in the beginning of the test i got two 11's, what is that about? also i think the iac motor only goes out after long idles or when it gets too hot. so i need to run the codes about tmrw to comfirm. also for the 02 sensors. could that 41 and 91 error code be because of my straight pipe with no cats?
 
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