Volvo: Performance, flame trap, vacuum lines

Question

my car is a 95 850 Glt 2.0.. the car performs great according to its mileage of 200,000 miles. the engine compression is good, my only complaint is the car lacks some power when climbing uphill, so my question is do you think my exhaust system might be the reason because of the age and the mileage of the car? maybe there is a backpressure causing the loss I guess. and there is a slight hiss coming from under the instrument cluster when I'm driving the car between 1200 to 2200 revs, do you think the vacuum lines might be it? I have used 97 octane rated fuel and seen that the car absolutely performs much better instead of 95..  I have also serviced and cleaned the flame trap and the throttle valve and the throttle housing with a carb cleaner.. the trap isnt replaced but the car appears to perform better, should I replace the trap? as usual I have been asking few questions instead of one so forgive me ok

Answer
Mete,
Yes the exhaust might be blocked, the fuel filter blocked, fuel pressure low or just an engine that is wearing out. You need to trace the hiss under the dash and repair it. I do not think that is a problem that would cause loss of power. Replacing the flame trap is a good practice to do every 20,000 miles.