[Richard]

I won't do a sales pitch again for TPMS, but I am a believer.

Relative to changes in ambient, here is how I use the TPMS. During our summer trip we saw morning ambient temps of 85 to 35 on travel days. I could see the tires were lower in the lower ambients obviously but I didn't touch the pressures. What I did do is compare axles, i.e were the two fronts still equal, four drives still equal, and tags still equal? I felt this was sufficient to tell me if the lower pressure was due to a leak or lower ambient pressure.