97 Subaru Fuel Problem

subaru
impreza

#1

I have a 1997 Subaru Impreza Outback. The problem is with the fuel delivery, I think. It usually only happens in the morning when I turn the car on and for about the first 15 minutes of driving. When I come to a stop, the car idles a little rough like it’s gurgling and wants to turn off, when I proceed to step on the gas it gurgles for a few seconds and the pick up is very sluggish and then it picks up back to normal. I changed the fuel filter and that seemed to help a bit, but it still continues. I feel like it might be the fuel pump, but after looking at parts online, I saw there are fuel injectors, strainers, relays, throttle position sensor??? Beyond the fuel filter and I do not what to change next. Here’s an interesting thing I noticed when I changed the fuel filter. My dad, a very skilled self taught mechanic, told me when changing the fuel filter, drain the old one and blow through one end and depending on how dirty the filter was, you could tell by the air flow from blowing in it. Well I did that and when I did, I blew out a little extra fuel that was in there but it was a muddy color, kind of rusty. Would this have anything to do with my problem? Could the gas tank or lines be rusting inside and causing the debris to clog up the fuel line? Or is the muddy/rusty color just from the filter? Thank you so much for any help you can give me.