I love these kinds of little problems. It only does it once in a while, and will inevitably stop if I take it to a mechanic.

At idle, SOMETIMES, there is a low sound that I can only describe as a "popping" kind of sound. The slightest touch on the gas pedal makes it go away, and it returns at idle. This is not the chirping sound from the throwout bearing in the clutch......I have gotten used to that sound, which is definitely a "chirp".

This is on a '96 Runner, 3.4L with about 109K miles on it. It runs fine with full power and no other symptoms. The gas milage seems good, and it has never done this before. Any ideas??? Maybe an emission control or some such item??

Thank You

 

Additional Info: I should have put this in......totally stock engine with no additions or changes at all, and my wife drives it every day which means that it rarely gets over 3500 RPM.

 

is it the exhaust that's popping?

 

Nope.....definitely engine compartment. I haven't had much time to search for the obvious disconnected hose, or the giant on-off switch that was inadvertently switched to the "off" position. Somehow I doubt I'll find either of those, so I wanted to toss this one to the yotatech sharks and see if I can get some ideas about how to approach this.