1999 Four Banger Idles Fine (ish), Dies When Touching Throttle

I was driving down the freeway after just dropping off my girlfriend. The car was warmed up and ran fine on the way there (15 minutes). After a minute or two of being on the freeway coming back, my car started acting funny. It wouldn't idle at all and RPM's were doing strange things. The check engine light is NOT on. It wouldn't start, so I got it towed home.

Today I did some diagnostics and figured it was likely my fuel filter. I replaced the fuel filter, but still no dice. The engine will start, runs and idles semi-smoothly for a second, and then bogs down and dies as soon as the throttle is touched. I have pulled the fuel line coming into the fuel rail off, and when I try to start the car, plenty of gas came out. But not when I just had the car on run, only when the engine was cranking. Any ideas what this is likely to be? There is 108000 miles on the car currently.

Also, I do not know if this is significant or not, but in the back passenger side of the engine compartment, the black box which has a cable coming out of it (the cable goes to the throttle) makes noises with the key to "ON", as if something internally was moving around.


Thoughts?