Dies at a Stop Light

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Jan 18, 2005 | 01:50 PM

#16

BillyBob69

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From: Wheatland, Mo

IAC = Idle Air Control valve

Jan 19, 2005 | 01:54 PM

#17

92EBnTX

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Anyone with a 351W have specifics on cleaning the IAC? Or is the description BillyBob69 gave pretty close? I'm doing the job in a couple of days and need some guidance. Thanks.

Jan 19, 2005 | 01:58 PM

#18

BillyBob69

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From: Wheatland, Mo

I found that the IAC on the broncos is located at the front/top of the intake manifold. It went to the back side after 96.

Jan 19, 2005 | 02:03 PM

#19

92EBnTX

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Is there any special instructions for the cleaning? I'd hate to spray something that doesn't withstand TB cleaner.

Jan 19, 2005 | 03:00 PM

#20

BillyBob69

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From: Wheatland, Mo

TB Cleaner wont be an issue. Just remember to dry it thoroughly before putting it back.

Jan 20, 2005 | 06:29 AM

#21

92EBnTX

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OK.... I cleaned the IAC last night and it didn't help much. So I guess I have to replace it now. Now, I have a popping sound (like backfire) coming from the air cleaner. Could this be related to a bad IAC? The sound only happens under acceleration. I had the engine replaced with a rebuilt one last weekend. The test drive after the install went without a hitch. Now, it idles badly and often dies at a stop light, while idling in gear, and while shifting from drive to reverse (and vice versa). I thought a new engine would help matters. I apparently am terribly mistaken. HELP.

Jan 20, 2005 | 11:32 AM

#22

greystreak92

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From: Gateway to the West

Ok, AFTER you clean it, there is a way to test the IAC to make certain it is working properly. With the truck warmed up to normal operating temp., shut it off. Disconnect the electrical connector to the IAC. Restart the truck. It should just barely catch and maybe run for a few seconds before it falls on its face and dies. If it does, turn it off again and disconnect the battery for about 5-10 minutes. Reconnect the IAC connector and the battery. Start the truck again. It should idle just fine now. If not, the IAC is suspect. You will need the calibration code from the drivers door jamb to order a replacement IAC. If your in-gear idle is still a problem, look to the TPS (Throttle Positioning Sensor) for the trouble. Again, if there are any codes in the computer, this would be the place to start. Knowing codes avoids a lot of hunt and hope when repairing or replacing parts.

Jan 20, 2005 | 11:54 AM

#23

92EBnTX

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You're a big help! I'll try that when I get home. I do have a couple more questions though:

-Would the TPS affect shifting?

-On this forum, I've read about burned out brake lights affecting engine performance. Does this include a burned out 3rd brake light?

-Would an IAC from an auto parts store do the job or do you recommend Ford parts?

Thanks again to you and all those who contribute to this forum.