At what temp does the three cylinder high idle kick in?

 

For you the chances are prolly 1 in a 100k, its some where around 30-25, but 3 sensors have to read certain temps and all 3 are different. You have to live in a colder climate to see 3 cyl idle.

 

had smarty for two years and it never kicked in. southeast texas dont get that cold

 

for mine, temp is around 25F... i did replace my IAT sensor prior to the smarty

 

The high idle around 25-30 is the regular high idle, not 3 cylinder high idle. The 3 cylinder idle doesn't kick in until around 0 degrees, and trust me there is a HUGE difference between it and reg high idle. The 3 cylinder mode will make you need to change your britches if you're not expecting it. I've read of a lot of people shutting it off thinking something was horribly wrong.

 

the 3 cylinder high idle is for arctic conditions