I thought the intake air temp sensor is the sensor all the way in the back of the intake manifold. That would make it post grid heaters. I clean the sensor every 3 months or so with electric parts cleaner. The sensor is always very dirty,thanks to the exhaust brake. I think this sensor plays a part of when the high idle kicks in. The reason I asked about moving it is because I rarely see temps below 32. F on the attitude display. I don't plug it in,it must be the grid heaters keeping the temp up. Even if it's 20. f I see IAT around 38-40 thats not cold enough to engage high idle,I think 32 or below will work