Arcing noise @ idle driving me crazy

[billy bronco]

I have a noise thats driving me crazy. Sounds like a leaking spark plug wire, (I know its not that) only does it at idle and sounds like its coming from the fuel injection rail. Car runs perfect in all respect but noise is getting louder. Do the injectors make a noise like this or some air or electrical valve. If I didnt know better I would say I had a bad plug wire, sounds just like an arcing HT wire.

1997 with 100K miles

 

[kcbhiw]

Are you hearing this from within the car?

I hear the same noise at times from both of my Miatas while standing in front of it with the hood open. It's just ignition noise.

 

[billy bronco]

I don't really hear it inside, but yes standing outside by the car and yes more with hood open and a tuned ear to it.

 

[mazdadude]

The two most common items for this noise are the HLA's, and plug wires.

Most likely it is the HLA's inside the valvecover telling you it is time to change the oil.

They can make a tic/arc sound, also could be the composite material that the spark plug wire insulators that go through and into the head. If your plug wires are not stock ones, or more than 30k miles old, or 5 years or older, replace them.

 

[aMaff]

probably the vibration on the IAC (on the bottom of the throttle)