The fix to my similar problem was the CPS.. Try another,,stranger things have happened !!

 

"""""i've also noticed the speedometer drops to zero when it stalls."""""

There's your clue. An O2 sensor, a CPS, or other sensors will not cause the speedo to drop suddenly. It will still read something until you actually stop. Power to the speedo and ignition is going away.

It's electrical - something is loose or shorting out. Start with the power distribution box - look at the bottom of it where the wires are.

Clean the battery terminals - check the wiring on the alternator.

Right after it stalls, try feeling all the wiring - looking for something hot.
Shake all the wires while running - underhood and under the dash. Jiggle the key switch.

 

Any luck with this problem? Mine is doing the same thing. My speedometer also drops to 0 so I've been chasing electrical shorting with no luck. Have replaced cam sensor, coil, and relay along the way. Fuel pressure is ok.

It is getting worse - used to run, stall and I could restart and go a little ways before stalling. Now it stalls and won't start again - though it does crank it just doesn't stay on.

 

cant believe i never wrote the fix!

i did what 'rrich' said, shook the all the wiring harnesses with the engine running and that made it stall out; turns out the ground strap that runs from the firewall to one of the rear valvecover bolts was rubbing on the injector wiring harness and exposed a wire. just to be dang sure, i took a jumper wire from ground and touched it to the exposed wire, and it cut right out.

fixed the wire and it never stalled again. till i hit a f250 broadside at 50mph..
THAT made it stall for good :/