C15 Acert Melting Wires and IVA stuck

We have a 2016 389 peterbilt glider with a MXS C15 Acert factory 625 motor. Ran great until 160k miles. Burnt the injector harness on #4 at the tip where connects to injector. Repaired, lasted a week. Replaced entire inner harness and injector, lasted 2 days. Truck went to CAT dealer replaced entire harnesses inside and out. Lasted 3 weeks. Always #4. This most recent time in the shop they tested fuel pressure, put a new test ecm, truck still skipped. They found the IVA sticking on #3 holding the intake valve closed. Replaced IVA housings, injector and injector harness again. Now the truck still has a miss too it under load and when it’s hot it’s worse. We haven’t had the truck back long enough to see if it burns 4# injector wire again. Does anyone have any ideas or have experienced this before? Also can the IVA holding valve closed cause internal damage? Or could there be internal damage that was the cause of the IVA TO hold it closed? CAT dealers can’t seem to figure it out and neither can we. Thank you

 

We’ve replaced #4 injector three times in the past 2 months and #3 one time

 

They just placed a test ecm on in their shop and load tested the truck on their in shop dyno. The problem continued so they put the factory ecm back on.

 

Correction. The IVA WAS HOLDING THE INTAKE VALVE OPEN. Not closed as original posted. Had a brain fart lol