Rune

Hi everyone, we have a funny problem with my friends new MTI 427
C5R engine.
It starts ok, idles kind of rough, have not done idle relearn procedyre yet.
After a while, my friend went trough different gears (idle standing still) and we shut her down.
Then we cant get her to start up again ???
It tries to start, but shuts down again.

With Ease scanner i looked at all DTC and cleared them, there was two B errors, cant remember #, but it was regarding battery.
a few U errors, and one Pxxxx regarding TCM something.
Not anything that should indicate engine failure......

After a little cool down period, engine started up nice again ? wtf.....
Same thing happen over again, go trough gears, shut down and would not start again.

pleeese help out if anyone know where to start..