Volvo: No Acceleration, volvo 740 gl, volvo 740

Question
Hi,  
I have a 1990 volvo 740 gl,  I've noticed lately that when I'm on the freeway and want to accelerate the car is unresponsive.  I can press the gas and it wont go any fast but it seems to slow down to the point that I have to pull over.  Everything else still works fine, but I have to shut the car off and then restart it in order to get it go again.

Any idea what could be causing this?

Thanks in advance,
Shauna

Answer
Shauna,
Do you feel the engine missing? If you do preform a tune up and see how that works. Test the fuel pressure and see if the pressure drops as the power is lost. Make sure that the fuel filter is new also. The correct pressure is 42psi idle and under acceleration go to about 47psi. See just how much pressure the pump will put out. Max pressure is in the area of 100psi.