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Hi Guys,

Have any of you experienced that when your vehicle is running on idle, RPM is stable at around 800-1000. Then, when you turn on the air-contioning unit, the RPM drops to around 600-800 only. I'm passed checking & ensuring the usual regular change oil, tune up, fuses, batteries, etc. No check engines, fault codes, etc. Vehicle is running fine even for long drives.

Mine is a 2004 XL7 with a H27a engine on AT.

Thanks!

 

[aquanaut20]

That is a sign that the idle control is not working.. Check the operation of the idle control device..

 

[[email protected]]

Thanks Philip...

Did you mean the throttle assembly?

 

[2013GV]

Thanks Philip...

Did you mean the throttle assembly?
View attachment 95812

No, he means the idle control circuit and its wiring, the IAC is part of the throttle body.
Does the car idle normally at start up when cold? as in fast idle then drops as it comes up to temp? if it does, chances are the IAC section is working fine. If this is the case its going to be between the AC and the idle control where you will need to look, when the AC clutches in, the idle should rise, so somethings not telling the IAC to operate when the compressor turns on.

 

[[email protected]]

Hi Guys,

Final update on this... finally got it fixed by replacing these two parts as suggested by all of you. Also dissambled and cleaned the whole throttle body to be sure. Lastly, I used a fuel additive with cleaning properties. Now my engine settles nicely between 800-900 RPM everytime regardless of load.

Thanks again for all the help Everyone!