Mechanics

HIGH IDLE WHEN I TAKE IT OUT OF PARK.

1997 Buick Lesabre • 127,000 miles

Replaced upper intake and gaskets, TPS, IAC, MAF, MAP, not all at the same time. Has new O2 sensors. Runs fine however sometimes when I take it out of park and put it in gear the idle goes pretty high, I go into neutral and it will slow down then I can put back into drive and it is fine. I thought it might be a defective IAC so I got another new one and it is the same thing. One thing, the battery was never disconnected for any of this work, there is no check engine light. The original upper intake had coolant getting into cylinders from the defective design on the EGR tube, the EGR valve is also new. Any ideas on what could be the issue? An help is greatly appreciated.
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Pcdj64
May 8, 2012.




Wow, lots of new stuff.

It sounds like you have a vacuum leak. You need the intake system smoke tested to verify.

Stop throwing parts at it and get it correctly diaged.

Roy


I am replacing original parts with new parts a little at a time.
Some was bad like the upper intake and a few of the sensors. The O2 sensors I did with the exhaust. I will look for a vacuum leak, thank you for the help.
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Tiny
Pcdj64
May 8, 2012.
Let us know how you make out.

Roy


No vacuum leaks, all lines connected, no dry rotted rubber.
Today it did not go to high idle when I put it in gear but it did stall the first time I tried to start it. It has lot of power, idles smooth at around 800rpm. If it was vacuum I doubt it would idle smooth or run very good.


Tiny
Pcdj64
May 8, 2012.
Is the check engine light coming on at all?
You will need a good scan tool to look at all the sensor data to see if everything is where it should be. Look closely at both the CTS and IAT.


Wrenchtech
May 8, 2012.
Here is where I sound like an idiot lol, what is CTS and IAT?
There was a check engine light a while ago that has been resolved with new sensors. No light now at all. So far today it has not idled higher when I put in gear but it did take a few tries to start it, it starts and sometimes immediately stops or slows fast and stops, when it finally stays it sounds like it wants to stall but catches itself, runs perfect after that. Well as perfect as a 3800 series 2 can run.


Tiny
Pcdj64
May 8, 2012.
Coolant Temp sensor
Intake Air temp sensor


Wrenchtech
May 8, 2012.
Both sensors are 15 years old with 137K miles, I was told to check the crank and cam position sensors but they are not turning on the light.
I did notice the car only acts up after it is warm, first start in the morning it is fine.


Tiny
Pcdj64
May 8, 2012.
Never since I have had the car has the temp gone over 1/4 of the way, even on a very hot day in traffic it is 1/4 and takes a while to reach even that. I changed the CTS and now it goes to half or a little above half. I also changed the IAT, it didn't look too healthy.
So far it has started and stayed running a few times without stalling or running at high idle, will keep you posted. Thank you much for the help.


Tiny
Pcdj64
May 8, 2012.
The intention was to test and not just throw parts at it but if it worked, great.


Wrenchtech
May 8, 2012.

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