Originally Posted by kauhane
Recently, I have been experiencing rough idle, sometimes stalling while in gear, especially if air conditioner is on...have read in forum this could be due to Catalytic Converter needs to be replaced; Lean Fuel Condition due to vacuum leak, unmetered air past MAFS (Mass Air Fuel Sensor), and/or the EGR Valve (stuck open)...Please reply if anyone has experienced these symptoms and perhaps some recommended solutions, thanks for the "brains" to a solution...
NO check engine light, start with cleaning your IAC (Idle air control) valve, throttle body and your EGR valve. Use a product called Deep Creep made by Seafoam and also give your engine a Seafoam treatment. http://www.seafoamsales.com/
. When there is tomuch Carbon buil up on your IAC valve, it's know for it to stick and can cause what you have described.
Once that has been done, will not hurt to give your Yukon a General Tune up, Spark Plugs, oil and filter. Good ,uck and keep us all posted,