Volvo: loss of power, fuel pressure regulator, vacuum leaks

Question
i have a loss of power mostly after the car has been running 10mins or more. the model is a 1992 960 24V. i have changed the spark plugs and air filter along the way examining hoses and vaccum pump. i also changed the fuel filter. it is wasting gas and almost feels like its about to die when i step on the gas, if im gentle on the gas it will regain momentum. im thinking its the MAF or fuel injectors. My dash light arrow is blinking along with the gear box economy and sport light. although i know it can be the trans i dont want to jump to the most expensive conclusion especially since when i first run the car it moves and grabs gears exceptional. could it be something to do with the O2 sensor also or is it mainly the fuel pump and fuel sensors. Hitting a brick wall here not very equipped with any special tools for diagnostics???any advice?, will be taken into consideration.

Answer
Mark,
What fault codes do you have? Read the trans ones also, since the arrow flashes. I have to think that the MAF is the next part to try. How is the idle after the car gets warm? If it is rough test for vacuum leaks at the intake manifold. They fail at number one cylinder mostly, however test the whole manifold. Test the fuel pressure and see if the fuel pressure regulator leaks at the vac line.