Starts, 35+ PSI fuel pressure, then engine cuts out, will not stay running?

I looked at the All-Data. DYS, agreement as you said there is a cost involved to use this software. I cannot find the price of the Tool/reader itself. I don't know if I am ready for this All-Data subscription. Ancel AD310 reader is on Amazon for $26.00. It says it's a CAN and diagnostic tool. As we all know you get what you pay for. I am at a loss as to what to do. I think I will stay with the plan and let Chevrolet reflash the PCM and start from there. Again, I will let you know what happens.

Thank you for clearing this up. I know that I need something more than the NT7X6 Foxwell. But I'm not ready for The All-Data subscription service as a DYS guy. I ordered what you recommended. If Chevy does not fix the problem and does not give me new codes to look into. It will be good to have this tool. As far as flashing a PCM I guess only Chevy, in this case or another manufacture has the software to do this operation. I know VW is very secretive. Dealers have to contact Germany to program an ignition key.

I do not know if you received this. The car came back from Chevrolet running/but with the MAF disconnected. As a novice, I can't see how the car can run without the MAF. Doesn't the MAF tell the PCM the amount of air so that the throttle body can adjust the gas to air ratio accordingly? I will replace the MAF and plug it back in to see if the car still runs. My situation is. Do I buy a middle of the road brand new MAF off Amazon? That is recommended for a Saturn L 300 3.0 for $64-$89.00, or should I get an original Bosh, PBT-GF30 from a salvage yard or Ebay seller for $50.00 if I can find one, chevy price for this part is $293.00 Genuine Bosh for this car of the internet is $149.00. Again, I am awaiting your reply. How best to precede. Glad the car is running, but I'm stumped as to what to do next.