That would be down my
There could be any number of bad connections, fuse connections, relays, chafed wires, failing sensors, I donno
, PCM's a pretty expensive place to start. Stuff like this always sucks, hard to duplicate, hard to find the commonality, it just takes time & testing.
I would take any tuning off you might have, go back to stock, take a good look at the fusebox for loose stuff, roll the wire looms under the hood over any place it might chafe (Valve covers etc.). Maybe have a good look at the IPR itself, make sure the tin nut's there and the wires look solid.
It can be a project
, but anytime I've resorted to Throwing Parts
at an intermittent problem I've felt pretty stupid when I found something simple I made into a Big Deal