Hunting idle, Pretty sure its the head temp sendor Options

[VaccaRabite]

Caveat: I'm using custom fuel injection (Microsquirt)

So this weekend my idle started hunting. I was pretty sure I had sprung a leak somewhere that was opening and closing a miniscule amount while the car vibrated at idle.

My idle would go from 1000 RPM (where I have it set) to about 1900 RPM for a few seconds and then settle back down again. Whatever, drove the car for 300 miles anyway. Only time when it became an issue was at stop lights and trying to get through the free bridge traffic jam between NJ and PA - and then it was just an added annoyance.

When I got home I did not find anything obviously wrong. I plugged my laptop in to see if my IAC had gone out of compliance. It was fine but I noted my "coolant" temps were all over the place.

Coolant sensor for me is the stock location head temp sensor, plugged into my ECU.

Are these things known for failing? Mine was giving readings with a 100+ degree swings every few seconds (I'm guessing cutting out), and my idle air valve was opening and closing trying to keep up, hence the idle hunting.

Zach