1999 Dodge Caravan High Idle Speed on start up

Tiny
SILEVSTRI99
  • MEMBER
  • 1999 DODGE CARAVAN
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 100,000 MILES
I have a 1999 Grand Caravan wit ha 3.3 liter engine. I changed the spark plugs today and had to remove the throttle body and the sir plenum to get to the back three. When I resembled it I have a problem with the idle racing up to around 5000 rpm on start up. I've gone back and checked all of my connections and vacuum hoses but everything seems to be in place. I also disconnected the battery to reset but that doesn't seem fix it either. Could this be related to the IAC motor?
Saturday, March 29th, 2008 AT 10:15 PM

8 Replies

Tiny
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  • MECHANIC
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It may, but I would still focus on a vacuum leak.

Use some carb cleaner and spray around the areas that you disturbed to see if a gasket is sucking air or crack etc.
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Saturday, March 29th, 2008 AT 10:21 PM
Tiny
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Is there a particular vac line that would cause this high idle.

And btw, thank you very much for the help!
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Saturday, March 29th, 2008 AT 10:29 PM
Tiny
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I'm not thinking vacuum line necessarily, may be at the plenum base. It's getting extra unmetered air it sounds like to me. The carb cleaner should narrow it right down. I assume everything got plugged back in okay.

Some of the vaious pcv hose dry rot and collapse or crack on those as a side note.
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Saturday, March 29th, 2008 AT 10:39 PM
Tiny
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Thanks, I'll take a look at it in the morning. I might have been shy when I was tightening down the plenum. The hoses didn't seem to dry or cracked.

Thanks again Paul! :)
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Saturday, March 29th, 2008 AT 10:48 PM
Tiny
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Do you have a torque wrench?
I can get the specs...OR you can get them here:
https://www.2carpros.com/kpages/auto_repair_manuals.htm
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Saturday, March 29th, 2008 AT 10:51 PM
Tiny
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I've looked around but can not find the specific torque specs. Do you have them?
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Sunday, March 30th, 2008 AT 2:53 PM
Tiny
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Found the specs, tightened the bolts down, checked all my vac lines and then pulled the neg battery cable off for 10 min to "reset the computer". One of the above worked and I'm back in business, thanks for all of the help!
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Sunday, March 30th, 2008 AT 5:17 PM
Tiny
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Just got back on line.

It is highly likely it was the retorque if there was any loosness in the bolts.
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Sunday, March 30th, 2008 AT 6:16 PM

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