I tried to make a gauge based on a formula between 2 PID's. I think my efforts are mostly right. I wanted to replace my 4 air temp readings with 1 that would give the difference between IAT 2 And Ambient. Sort of a 1 gauge Heat Soak reading. My result is reading the same as my IAT 2 which leads me to believe the problem in the formula is in the Ambient PID. One difference is that the Ambient PID is not a custom PID like the IAT 2. I wonder if this nice function is limited to just custom PID's and might not work with the ones packaged with Torque.