What does the IAC do?

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b1g$t33m3r

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I've had this problem where my '99 4runner 2wd, after a good city traffic warm up, will start idling strangely. While sitting at a traffic light the idle will fluctuate and finally die (in gear and only in ambient temps. over 80 degrees). I've had people tell me that it could be the IAC. My question is what does the IAC do? Does the IAC react to hot temps? I have tried most everything. Mass-AF sensor, vacuum hoses, fuel filter, O2 sensor, cleaning the manifold, you name it...I've narrowed it down to something that is effected by the heat. Is the IAC effected by the heat or hot air temps.? (check my previous threads it's been going on for awhile):redbrick::redbrick:
 
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The IAC (idle air control valve) controls the idle electronically based on engine conditions. So yes temp is an engine condition that can change the idle control valve. Research on how to clean IAC and throttle body.
 
Follow-Up

b1g$t33m3r said:
I've had this problem where my '99 4runner 2wd, after a good city traffic warm up, will start idling strangely. While sitting at a traffic light the idle will fluctuate and finally die (in gear and only in ambient temps. over 80 degrees). I've had people tell me that it could be the IAC. My question is what does the IAC do? Does the IAC react to hot temps? I have tried most everything. Mass-AF sensor, vacuum hoses, fuel filter, O2 sensor, cleaning the manifold, you name it...I've narrowed it down to something that is effected by the heat. Is the IAC effected by the heat or hot air temps.? (check my previous threads it's been going on for awhile):redbrick::redbrick:
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Just a follow-up...After doing everything but the IAC, (almost). I had a friend who's an ex GM engineer take a look and he noticed that there was almost no light seen when looking through the grill at the radiator... he thought the radiator was dirty so after a hi-pressure blast of hot water it looked better but upon closer exam I noticed that while it may have been dirty there were dozens of the radiator's fins bent so that there was very little air circulating...So guess what I'm doing this weekend??? That's right I'M BENDING FINS! I hope this solves the issue!!! :pray: :pray: I'll have a follow-up to this follow-up...Thanks to those who gave the helpful info.
 
b1g$t33m3r said:
Just a follow-up...After doing everything but the IAC, (almost). I had a friend who's an ex GM engineer take a look and he noticed that there was almost no light seen when looking through the grill at the radiator... he thought the radiator was dirty so after a hi-pressure blast of hot water it looked better but upon closer exam I noticed that while it may have been dirty there were dozens of the radiator's fins bent so that there was very little air circulating...So guess what I'm doing this weekend??? That's right I'M BENDING FINS! I hope this solves the issue!!! :pray: :pray: I'll have a follow-up to this follow-up...Thanks to those who gave the helpful info.
Click to expand...

Use something like this

Radiator Fin Straightener
 
This is interesting because I knew that I had seen one of these tools, but all of the people that I asked said that they had never seen or heard of these before. Thanks for the link!
 
You might as well get a good replacement, oem or koyo. They are not that much and probably needs it anyways.
 
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