Stalling problems

I am having a problem with my 2015 5.7 fuel injected engine. It stalled while under way and would not restart. I have had mechanic try and diagnose issue and there appears to be something wrong with ECM. I have power into ECM but no power to fuel injectors. After 4 weeks of back and forth with manufacturer I finally got them to send me new ECM. I was able to get engine to start with new ECM but it stalled after about 1 minute. It does restart immediately but does the same think. Runs for about 30seconds to 1 minute and then stalls. I have checked fuel rail and I have 55psi. I replaced MAP sensor and it did not make difference. Cant seem to figure out what is causing issue. Mechanic thought ECM or harness issue. The manufacturer also sent new coil which I installed. Going to hook up Diacom to read computer and see if any trouble codes. Mechanic cleared them all out after installing new ECM.

I am stumped hoping someone on this forum has an idea.

Thanks
Matt

a new ECM won't have any DTCs stored in it....

" No power to the injectors" means no +12VDC or no trigger from the ECM? Does the same issue occur with the new ECM?

The Diacom tools will also show you the inputs and outputs of the ECM and can be very helpful for troubleshooting.....

Was the fuel rail pressure checked the whole time the engine was running or just once and was it done at idle or in gear and at RPM?

I'd say you need to verify the problem is lack of fuel or lack of spark and then go from there....

The new ecm did not correct problem. I check fuel pressure at rail and it is with in specs. I also checked have 12volts at ecm, coil and spark plugs. No codes in old ecm or new. Checked all the relays in fuse box and all tested fine. Decided to check all the sensors I had access to see if they working properly. Based on what I read the crackshaft position sensor located right below distributor could cause this issue. It tested ok when I disconnected sensor it immediately produced trouble code. I decided to disconnect the throttle position sensor on the throttle body and low and behold the engine started and ran. If did not idle very well but did run until I shut it down. There was a trouble code in ecm for that sensor. I thought I had issue with throttle body and position sensor last year when I had an uncontrolled acceleration problem. The engine would suddenly increase rpm for 3300 to 4000 with any movement of the throttle. I would also not respond to the throttle if you tried to reduce rpm unless you lowered all the way to idle. Will call manufacturer on monday to see if they think the throttle body or throttle sensor could be causing the issue.