Help with 99 7.3 Stalling, loosing pcm power

78f100

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Ok I had a 99 7.3 dropped off at the shop that is giving me fits. It runs fine but randomly stalls, turn key off, restarts fine. May go 1 min or run for hours before it happens again. Heres what I have done so far, first changed cps sensor, unplugged fuel heater, IPC had oil coming out so replaced it and pigtail. Same problem after all this, so it died with ids running diagnosis and lost communication with pcm. I swapped pcm, batteries and cleaned every connector pin and socket with Mac master connector cleaning kit, on pcm, idm, engine harness plug, under hood fuse box, under dash fuse box, and both harness connectors on cab. I even cleaned all the fuse contact pins and relay pins, the truck has set up under a barn for a long time. The customer had already changed out the under dash fuse box because when it stalls you can hear relays click right before it dies. I reinstalled the old one after cleaning it up with the same results. When it starts to stall sometimes (2 times to be exact) it went to idle even with the throttle pressed, as long as I hold the throttle it will stay at idle, if I let completely off and repress the throttle it works perfect. Last time it stalled with the ids on it the wait to start light flashed as if I had cycled the key, but ids lost communication. I pulled the pcm with key still on, had power to pcm, plugged it back in and it started. I forgot I also replaced the ignition switch.
I know it's loosing power to the pcm just can't make sense of why or how, it always restarts.
Some of you guys please bounce ideas off me , I'm about fed up with this thing but can't let it beat me...lol.
Sorry post is so long but appreciate any ideas.
 

78f100

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I swapped it out also, with a good one from a running truck. I have swapped every relay in the truck.
 

6.0 Tech

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Check pin fit on the inline connector on the lh valve cover, and at the pcm maybe. Batteries good and alternator charging properly?
 

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