1997 Chrysler LHS High idle at all times

1997 CHRYSLER LHS
109,000 MILES • 6 CYL • FWD • AUTOMATIC
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JIM VANVALKENBURGH
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Recently my 3.5 engine idle speed started to increase. At first it went up a few hundred RPM, but lately has increased to 2200 RPM. At a cold start it will idle at 1500. Within 5 minutes the RPM will rise to 2200. I checked vacuum lines, cleaned the idle control motor, nothing I do seems to effect it. The check engine light comes on and then after a day or two it will go out for a day. I strongly suspect that too much air is getting into the manifold. I removed the air cleaner and blocked airflow to the plenum and still there was no change in RPM's. What am I missing?
Feb 13, 2008 at 12:13 PM
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MERLIN2021
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Try unplugging the MAF, and check the throttlebody for binding or worn shaft. Get the codes read! Autozone will do it free, then post the result...Even if the light is out, you have frezze frams data, it will tell you what conditions set the code, and what the code is!
Feb 13, 2008 at 12:23 PM
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JIM VANVALKENBURGH
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What do you mean MAF ? I have an MAP sensor (manifold absolute pressure). Did you mean MAP ?
Feb 13, 2008 at 2:10 PM
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MERLIN2021
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MAF=Mass airflow sensor it is in the intake air plenum, usually just above the air filter box, dont remove it just unplug it..only as a test to see if your condition improves!
Feb 14, 2008 at 7:20 AM
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MERLIN2021
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It might also be worth your while to buy a scanner, some are in the 30-40 dollar range and can read the P codes in all 96 thru 2008 cars sold in the USA...
Feb 14, 2008 at 7:23 AM
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MERLIN2021
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Check the TPS and on the right strut tower ther is a relay for the manifold tuning valve...Unplug the IAC se what happens
Feb 15, 2008 at 7:41 AM
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GARNZY
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serviced a car like that once,it turned out to be the big hose going to the pcv was cracked and just got bigger over time or once it heated up enough.those hoses are thin walled and not very durable,
Mar 29, 2009 at 7:34 AM