If you determine it is indeed the fuel pump, there are a few tips we can give you to make the R & R a little less frustrating. I recently did this on a 95 960.

DEWFPO
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1998 S90 071,245 and 1995 964 154,100

Well that could be your fuel pump, you really need to hook up a set of fuel pressure guages and monitor the power supply to it. See if the power supply remains constant and see what the fuel pressure does in that time. You could just as easily have a bad pump relay or a faulty pressure regulator.

If it is the pump then yes it is part of the sending unit which is located underneath the black access panel in the trunk. No, it is not necessary to drain the tank to pull it out, although I would recommend doing it on less than a full tank of fuel as you will spill some getting the unit in and out. You will need a special tool to loosen the big plastic ring that holds it all together but if you are careful you can get away with using a large screwdriver. But if you are not careful you could damage the retainer and then you are screwed. Getting the sender out is not bad but trying to fish it back in and keep the gasket positioned properly will test your patience big time.

How long and how hard? Well I have no idea of your abilities or the tools you have access to, so god only knows. I can tell you that if left uninterrupted, no phones or customers that want to watch/help, it takes me about an hour to do one of the late style ones like you have. As far as difficulty goes I would say on a scale of 1-10 it is in the area of 5 or6. The only reason I rate it that high is because the late style senders can be a bear to get back in and get the gasket positioned properly, otherwise it really is not that bad, aside from having to work either stretched out or doubled over in the darn trunk!

Mark