Fast idle 1999 Toyota Tacoma

Tiny
MABER144
  • MEMBER
  • 1999 TOYOTA TACOMA
  • 187,000 MILES
Replaced ICV and computer. All other components seem to be ok.
Idles about 1000-1100 RPM in drive. In neutral from 1400-1700 RPM.
V6 3400 duel cam automatic.
Friday, December 9th, 2011 AT 11:59 PM

15 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,724 POSTS
Have you checked for vacuum leaks? Are all electrical connections in good condition, not corroded, and tight to the IAC?
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Saturday, December 10th, 2011 AT 12:03 AM
Tiny
MABER144
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Will check again and get back but haven't heard or seen aything strange. Thanks. Will get back to you
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Saturday, December 10th, 2011 AT 12:07 AM
Tiny
JACOBANDNICKOLAS
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Check for vac leaks too.
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Saturday, December 10th, 2011 AT 12:08 AM
Tiny
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Where is the best place to hook up a vacuum
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Saturday, December 10th, 2011 AT 12:28 AM
Tiny
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You can put a vacuum gauge on any intake ports.
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Saturday, December 10th, 2011 AT 12:31 AM
Tiny
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Thanks.
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Saturday, December 10th, 2011 AT 12:38 AM
Tiny
MABER144
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Vacuum steady at 21 inches engine at temp. Idle in park 1500RPM in drive 1000rpm.
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Saturday, December 10th, 2011 AT 12:50 AM
Tiny
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That sounds good. You need to recheck the IAC connection and wiring.
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Saturday, December 10th, 2011 AT 3:19 AM
Tiny
MABER144
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Okay I will. Idle cold with IAC hooked up 1300 park 800 in drive. No diff when upluging IAC.
Normal temp IAC hooked up 1500. Disconnected 900 idle 750 in drive.
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Saturday, December 10th, 2011 AT 3:59 AM
Tiny
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Remove the IAC and make sure the pintal at the end moves when the key is turned on and off. IF it doesn't, check for power to it.
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Saturday, December 10th, 2011 AT 5:58 AM
Tiny
MABER144
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I will have to do this in the am. The truck is back outside. I thank you for all your help and will be in touch tomorrow.
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Saturday, December 10th, 2011 AT 6:02 AM
Tiny
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I'm glad to help. I just hope I can get you pointed in the right direction.

Take care,
Joe
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Saturday, December 10th, 2011 AT 6:06 AM
Tiny
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Sorry I didn't get back but just a few questions.
1. Does the IAC get a signal from a temp sensor and if so how and where is it.
2. How do you check to see if one wire is keeping the IAC in high idle mode.
3. The temp gauge on the instrument panel works fine with great heat.
Thanks, Dave
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Sunday, December 11th, 2011 AT 6:35 PM
Tiny
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No to the temp sensor. The IAC receives signal from the PCM. Remove it to see if it is moving while a helper turns the key on and off.
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Sunday, December 11th, 2011 AT 11:06 PM
Tiny
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The flapper, as I call it, with key on has resistance, with key off moves freely. The valve is cold but doesn't open with power to it. Just resistance. I get the same results with two different computers with the same number, Toyota ECM 89661-4460.
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Tuesday, December 13th, 2011 AT 2:51 AM

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