Folks,
My 95 850 NA has been reliable, clean running, and shows no trouble or emissions codes, but doesn't have a lot of power. It never has but it is definitely not getting better with age. It occurred the fuel pressure might be marginal, due to aging of the fuel pump. I am thinking of the pump because by eye the injector spray pattern seems ok and the fuel filter is far from old.

I get about 35 psi or a bit more but it wanders around 2-3 psi or so up and down at idle. If I rev the engine the pressure will definitely drop by a couple of psi and when I return to idle, the pressure will overshoot for a few seconds. I would think the pressure should be very constant, and I have seen a constant pressure on other cars.

If you've measured your pressure, what is it and is it constant or not?

If I cut off the engine the pressure rises to about 40-41 psi and will hold there for many minutes, so injectors seem not to be leaking. To me it seems possible the pump is not keeping up with demand, and/or the regulator is marginal.

thanks
ksg