Wierd Noise

I have a 1988 Delta 88 w\3.8L V6. I am having a "vacuum cleaner" sound coming from the rear of my car. I do know my muffler has a few small holes, would the exahust make that kind of noise comming out of these holes or the fuel pump make that noise? Thoughts?
Thanks

If you just replaced the fuel pump with an aftermarket pump, I've heard then be quite loud at first. However you should be able to identify it when you turn on the key before you start the car. I"m leaning toward either the muffler, or possibly a bad wheel bearing or tire. You can rule the last two out if the noise persists when the car is sitting still.

Yeah, I just replaced the fuel pump a year and a half ago and I think it may be getting louder. So since it is getting louder is the pump going bad? It still has good fuel rail pressure around 47psi.

id definatly lean towards the exhaust my bmw has an exhaust leak and it make the same kind of sound your describing but do what tri-power said have someone turn the key but dont start the car and listen for the sound the fuel pump makes if thats it then check your fuelpump and if not then id definatly lean towards the exhaust

45 psi I believe is the suggested pressure, so if you are getting 47 then it should be fine. I instaled an aftermarket pump in my brothers 91 88 and we noticed that it was louder than OEM. Not to the point of aggrivation, but you could hear it running while driving if the radio was off.