[71K1500]

Thanks for the response everyone.
The engine shuts off as if the ignition is shut off. Just like turning the key off. Everything else seems to work fine. My son bought the truck like this with a 5.7 tbi and 700r4. The farmer who had this changed it over years ago. Ive changed out and tested iac, cap ,rotor, plugs, pump relay, etc.
Im sure its electrical but cant duplicate it in the shop. It only happens when throttle is released such as slowing down and ocassionally at an idle. It will crank over and start right back up but sometimes have to crank 2 or 3 times. It never loses power or shuts off when on throttle or cruising speed.
I dont think its fuel related as it never stumbles. Its as if the key is turned off. Im thinking of replacing the ignition switch and trace from there.
Ive also posted on Chevytalk site and have suggestions on the pickup coil and icm.
Jeff