JimmyK

Hey Spooler, thanks for the reply man, I recognized your name from the many threads I've seen over the years!

I inspected the grommit and quite a bit of harnessing with a snake cam and it looks great*. The harnesses also have continuity from the IPDM E/R to the ECU where they need it or makes sense, but I didn't get to shake the cables in all the areas or vibrate it the way the car does. I also didn't get to check all the connections to the ECU from the IPDM E/R of course, since it doesn't seem to be shorted when idling.

The ECU connectors all look brand new thankfully, no green corrosion. I will take the camera and inspect the top, sides, and back side of the ECU to see if there's any sign of water getting in. Thanks for the suggestion.

Could it be something that doesn't get actuated until the car starts moving? I suspected the EVAP Canister Vent Control Valve since that seems to be static while idling, and logically should start venting when fuel sloshes or builds pressure in the canister or tank.

Beyond what's listed in the General Information portion of the FSM, do you have any better ways to test for Intermittent failures/shorts? I have a data record function on the OBD tool I use, I could record the data and see what changes right before the ECU stops communicating but that's a stretch.

Thanks again for the reply and thoughts, if you have any other ideas let me know and I'll keep checking them. I can also take some pictures with the snake cam.

*Looks great aside from the Crankshaft Position Sensor (which comes off the ECU and was tested from the ECU pins for short-to-power & short-to-ground. I also shook the crap out of that one by its jacket using a snake grabber tool to see if it was an intermittent short caused by vibration, but it didn't cause any failures while idling or didn't short while the car was off and being electrically tested.