Just recently my 94 850 Turbo with 221K miles has started to randomly stall. I can be driving on the highway or sitting at the drive through. Most of the time I can't restart the vehicle right away. Generally within 20 minutes it will restart and go a day or two without it happening again. I pulled the codes from A2 and they were related to the O2 sensors (check engine was already on because of the O2 sensor codes). The first few attempts to restart the car it will usually start stutter and die. Other times it will just turn and turn with nothing. Finally it will start and drive like nothing was ever wrong.

I'm having trouble figuring out what is causing the problem, partly since it is intermittent and won't stall when I want it to! Here's what I've been able to look at:
- Pulled the vacuum, seemed good at 17HG idle. It shot down briefly (~5-10) if I revved the engine but came back up.
- Pulled the codes, nothing related to the Cam Position Sensor. I replaced that in 2006.
- Doesn't seem to be the ignition switch, since when it dies the lights on the dash are all on.

The fuel pump and relay are original, so I was thinking it could maybe be one of them.
Before the random stalling started, I was having problems starting the car if I filled the gas tank all the way up (up to where the gas pump popped). If I accidently filled the tank, I could usually get it to start by removing the gas cap, start the car and put the gas cap back on.
Don't know if it's related, but makes me think there is some fuel system problem.

I'm out of ideas, and short of just throwing in a fuel pump and/or pump relay, I'm at a loss of what to try next.

Any ideas would be greatly appreciated!
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Scott K - 1994 850 Turbo