I had a rough idle on my 2004 srx 3.6L Had no codes only ran rough and shaking at red lights like a stuck EGR value. Checked for vacuum leaks.Tune up didn't help. Ran great when cold. Found out the camshaft actuators were sticking a little remove and cleaned them and now it runs great.
I have a 2012 SRX with 80K on the odometer...at times when sitting at a light the idle will stumble...been doing it forever with no ill affect....I would suggest leaving "ECO" mode off since that tends to drop the rpm's at idle...that's all I got