So close

[JTinSC]

After a way too long term engine swap my son's '11 Aveo lives! (Kinda). While sorting a clutch issue the car failed to start. It had been brought to temp several times and driven 10-12 mi at this point. Drained way too old gas (to dry tank wiped out). Started right up, ran like a champ. Drove it around, drove it to work, went to (almost) fill up at lunch time, stalled as i arrived back to work, will not restart. Same symptoms as pre fuel purge... Will pull fuel pressure and compression tomorrow. Read similar symptoms related to maf sensor (?). Ideas please, it is way past personal at this point.

[EAD15]

Try loosening the gas cap the next time it won't start. If you hear air rush in and/or if it starts immediately after opening the cap, your issue is likely it's pulling a vacuum and dying from fuel starvation.

[JTinSC]

Noted, thank you. I did have pressure at the rail after failure to start, but unknown during cranking (no gauge, just purged/primed the rail to check). I let it sit all afternoon, then it fired right up. Already arranged a ride so I did not drive it home last night. Started right up again this morning... Not enough data points with only two instances, gonna drive home this evening and continue evaluating closer to the tools.