Engine idle too high

Tiny
HARLEY97
  • MEMBER
  • 2006 CHRYSLER TOWN AND COUNTRY
  • 73,000 MILES
I have the 3.3 liter engine and the idle speed is around 1,100-1,200 rpm's. I replaced the IAC valve and cleaned the throttle body with no change to the idle. I've checked all vacuum lines and there are no leaks. Is there something else I'm missing?
Thursday, November 14th, 2013 AT 2:28 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,053 POSTS
The computer tells the IAC where to set the idle, so that isn't adjustable. Are you certain there are no vacuum leaks? Did you check using carburetor cleaner or something similar?
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Thursday, November 14th, 2013 AT 3:24 PM
Tiny
HARLEY97
  • MEMBER
  • 3 POSTS
Yes I have. No leaks detected. Also changed the TPS. Still idling at 1,300 when at normal operating temperature.
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Thursday, November 14th, 2013 AT 4:34 PM
Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
What are the short term fuel trims? I agree, it sounds like a vacuum leak. The most common hose to forget is on the passenger side, just behind the air intake boot. Check there. I have left it off myself! Haha. Nobody is perfect.
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Thursday, November 14th, 2013 AT 5:12 PM
Tiny
HARLEY97
  • MEMBER
  • 3 POSTS
Do you mean the hose on the lower back side of the throttle body? That has been checked.
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Thursday, November 14th, 2013 AT 9:35 PM
Tiny
MADMIKE1735
  • MECHANIC
  • 951 POSTS
Yes that is the hose. Bummer! Your going to need a scan tool to check short term fuel trim. If you don't have access to one, it may be cheaper to bring to a shop for diagnosis, then repair yourself.
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Saturday, November 16th, 2013 AT 4:48 PM
Tiny
RJSCHEWY
  • MEMBER
  • 1 POST
  • 2006 CHRYSLER TOWN AND COUNTRY
  • 3.3L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 70,000 MILES
Started when check engine light came on with EGR code. Changed it, still high idle, then light came on again. Now it is IAC then changed it. Still high idle, then light came on again. Now saying high idle check for vacuum leaks. None change PCV value, change plenum thought it would be the problem. Got any other suggestions?
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Monday, August 14th, 2017 AT 8:09 AM (Merged)
Tiny
KASEKENNY
  • MECHANIC
  • 18,907 POSTS
I have seen this a number of times when this sets these different system codes and has the high idle. This is almost surely a vacuum leak that we are just missing. Basically when unmetered air comes in the PCM is trying to use these different systems to try and adjust for a lean condition. When none of them work it starts setting codes.

Here is a guide that will help once and for all find this leak so we can repair it and all will be resolved. You will need to do a throttle learn which is simply 3 deceleration in a row from 60-35 MPH with no throttle or brake input.

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please let us know what happens and we can go from there. Thanks
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Friday, April 17th, 2020 AT 4:14 PM

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