The interesting thing is that you noticed the engine idle was a little higher at idle and the IPR values were higher as well. You did not provide the actual ICP pressure reading. To me, based on your symptoms and the high idle I bet your ICP sensor is in fact failing. When one does this it is what we call "biased" and yes, it can happen intermittently. If you notice that the concern does not return after disconnecting and the reconnecting the sensor then a poor connection is suspect.
Unfortunately, it happened so fast that I wasn't able to see the HPOP (ICP) pressure readings.....I just noticed the IPR % Rate jumping around..higher than normal. It did the fast idle thing the first time I came to a stop, and then did the rough idle thing the next two times it acted up.
So far, it's been 3 days and 900+ miles without a single hiccup. Maybe I will just replace the ICP sensor for the hell of it.....worst case, I have a spare if I never need one.
Without it trowing a code, or consistently acting up...it's going to be hard to troubleshoot the issue.
Is it unheard of for a new-ish (1yr old) oem ICP sensor to start acting up?
2005 F250 6.0 PSD, ARP Studs, Felpro HG's, EGR Delete, IPR Coolant Filter, Bilstein 5100s, Blue Spring Mod, IDP Custom Tunes