Truck dying when at operating temp

[glmoore0001]

2006 Tahoe 5.3 flexfuel
When at operating temp, truck may run for 15 minutes or an hour and a half. After it cools down, it will start and drive again. It just quits, no sputtering, nothing but crank when you turn the key.
The first time it died, there were no codes. I had fuel pressure in the high 30's, spec I read said it needed pressure in the 50 lb range and that failure of the pump was a common issue. A Delco fuel pump was installed.
Second time it happened it threw a P0338 and a P0068, camshaft position sensor and mass air flow.
The car ran fine when it ran, so I am guessing the position sensor.
First of all, will a failing cam position sensor kill the car as described in the above?
Second, I changed the oil pressure sensor without pulling the intake, can I do the same thing with the cam sensor?
Thanks... Gary

 

[Fless]

It should run without the cam sensor signal, but with possible long crank times. But a P0338 seems to be related to the CRANK sensor, so I'd be looking at that circuit and sensor.

To answer your other question, the cam sensor can be changed without pulling the intake. I'm sure you know that it's tight back there.

After changing either cam or crank sensor, and when you get it running, a CASE relearn should be done in order to sync the two sensors. Otherwise you could have odd misfire codes and long crank times.

 

[glmoore0001]

It should run without the cam sensor signal, but with possible long crank times. But a P0338 seems to be related to the CRANK sensor, so I'd be looking at that circuit and sensor.

To answer your other question, the cam sensor can be changed without pulling the intake. I'm sure you know that it's tight back there.

After changing either cam or crank sensor, and when you get it running, a CASE relearn should be done in order to sync the two sensors. Otherwise you could have odd misfire codes and long crank times.

I must have read the crankshaft sensor fault wrong, sorry about that and thank you for posting.

 

[Fless]

With a scan tool you might also read what the coolant temp sensor is reporting to see if it's mis-reporting when up to temp. Don't rely on what the gauge indicates.