Missing and no power on accelleration

I recently bought a 1993 Chevrolet Cavalier from a guy near by and so far it's been running fine. Today though, going up a short hill with my AC on, it suddenly lost power and I was luckyto get it over the top. Pulled off the road and tried starting it again. It idled fine, but when I put it in gear, the whole car would shake and when I tried to give it gas, it would sputter and shake. I barely limped it home never getting it above 45 MPH though the tranny kicked in to passing gear, and up small inclines I was lucky to only drop to 25 MPH! Thought it was a dirty fuel filter, so I replaced it. The fuel filter was indeed dirty but that did not fix my problem. After a few minutes of idling, it starts shaking again, and there is no power for accelleration. There is a slight hissing noise from the back of the engine but spraying the engine with carb cleaner to find a vacuum leak doesn't point anything out. I am at a total loss as to why it's doing this. Tried looking at many other sites and liked the organization of this forum so decided to ask here.

Anyone have any ideas what is going on?

what about spark have you check that

Just checked. The plugs are fine.

friend at work had the exact same problem.

He found and then repaired a bent gas pick up tube connected to the fuel tank.

he had to drop the fuel tank....uck! but it fixed it.

get your fuel pressure checked