[snowman518]

HELP!! I have a 2007 Xterra. I have had the plug/wires changed. Throttle body cleaned. Fuel system cleaned. O2 sensors replaced. Truck still idles at just above 500 whether in P, D, N, or R ONLY when warmed up. It does NOT hesitate, shake, lose power, stall or idle rough. Its a very smooth idle but so low that the throaty sound reverberates in the cabin. I have had ALL types of diagnostic tests done and nothing comes up other then the O2 sensors which were just replaced. The shop claimed to have done an idle air intake relearn but nothing has changed other then the idle is now at its lowest.
Before I am forced to take to the dealer, is there a possibility of a vacuum leak, exhaust leak, or I have read could be the PCV. . .
I have been told by many that the 600 +- idle is normal and others have said it should be at around 750. Does not seem normal to me as it only started happening after I had the routine maintenance done.

 

[Mogman]

Factory specs for no load idle speed is 575-675 rpm.

 

[snowman518]

Considering the only real issue I have is that when it idles to a certain point, that the sound can reverberate so low in the cabin and be ear ringing. I assume its either a new muffler I need or replace the Cat convertor. At normal driving and stuff, its not unusually loud at all.

 

[Mogman]

Maybe you have a loose heat shield.

 

[snowman518]

Naw, Ive had all of them clamped down. . wonder if one is clamped too tight to something not allowing proper movement. . .
Anyway, going to get the PCV valve changed. Most likely has never been done at over 100k miles. Its a shot in the dark and cant hurt.