Josh mentioned a vacuum leak could cause this.
I hear that you can locate a vacuum leak by using a propane.
I found this in the DML archives.
"With the engine running, take a propane plumbers torch
and open the valve but do not light the torch. Aim the nozzle around the
hoses and intake manifold, wherever you suspect a vacuum leak. When the
engine RPM picks up, you have probably found the leak."
>Date: Thu, 1 Jun 2006 16:28:55 +0000 (UTC)
>From: marc.henri@sdc-dsc.gc.ca
>Subject: DML: 94 Dakota 5.2L High Idle when warm
>
>Was wondering if anyone else experienced problems with high idle on the
5.2L
>Magnum. I've replaced the IAC motor, so far and still the same problem.
When
>first starting the truck the idle appears to be normal -- however after a
>couple of minutes the idle gradually shoots up to about 1500 rpms and
stays
>there.
>
>Any suggestions would be appreciated.
Victor Williams
Marietta Ga
1995 CC Sport 2wd,5.9l,5sp,3.55LSD,MP sp intake,Flowkooler,
Jardine 3" catback,Flowmaster 70,CarSound Cat,Tow pkg
.
.
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