William Kisselstein

P0157 is O2 sensor low for bank 2 downstream.

Have you tried this? Crank 15-30 seconds, stop, crank again. Does it start?

Mine I had to do this for a very long time, before the regulator quit. There were really no other symptoms beyond a hesitation at idle in gear. I had presumed it was a weak pump, but it was the regulator letting the fuel drain back to the tank. You could crank it forever that first shot and nothing, but if you stopped for a moment and tried again, away it would go. Luckily it was here in the driveway when I went out and it would not start at all.

Like I said before, when the regulator fails, the fuel pressure is present, but the fuel all cycles back to the tank. I suppose you could verify this by disconnecting the return line somewhere and running it into a bucket. The lines just use snap clips, but I don't remember if any of them are convenient to access to try this.

The only other thing you can do is look at your live data and scroll through for anything that is out of range. The same van during the summer previous developed a no start when hot condition. I discovered the temp sensor had failed and was telling the computer it was -68F - when it was in the mid-80s outside. This had the computer adjust the mix and timing so far out it would not start if the engine was hot.