I have an 850 turbo that turns off every so often. It is becoming a pain. It just dies. I thought it was the fuel pump so I replaced it. I am going to replace the filter and relay next. Also my battery is weak so could that also be a problem, for the relay? Any Comments on what I should do to it, besides taking it out and shooting it ;).

If you have a bunch of stuff hanging on your ignition key try driving with just the key. If that cures it the problem is the ignition switch ... and the "stuff".

A weak battery will cause your alternator to work harder, and may cause hard starting. Unless your battery conections are loose and corroded, that should not be a problem.
You should have replaced the fuel pump relay before replacing the pump, it is much cheaper.
There are no codes in A-2 or A-3, right?

Klaus
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The 164 has a new home, all I am left with are a 95 854T and a 98 V70R :)

What happens when it dies? Do the instrument lights come on, or does it just have no (engine) power?

Will it restart? If not, how long before it will?

How about OBD codes?
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850 / Mini

When the engine dies what happens to the other electrical items on the car? Have you ruled out a poor connection in primary power and also a poor ignition switch? Might try with engine running at idle wiggling some things around and seeing if you can induce the problem.

The dealer did me with a fuel pump and it still died. The folks on this site recommended the fuel pump relay be replaced. Easy to do yourself. Part is around $55-70 (dealer charges $90). Volvospeed Bay13 has a how to link. Takes five minutes and your good.